HARRY'S POV
It took two days of studying different expansion rune scams on GAI and combine them, one day of making the new scam work by changing the runes into the language he created, one day of finding the right intent he needed and smithing the metal to the right shape, and another day that he had his AI attach the runes on it.
But at the end of those five days he created a big metal closet which once inside seemed to be as large three football stadium. (AN: not American football.)
Then another two days where FACTORY and all of its workers worked non-stop while Harry, Fred, George and Dobby worked on organizing the world inside with the needed equipment, products, etc... and add a few needed enchantments like the sky enchantment from the Grand hall in Hogwarts, temperature adjustment, indestructibility, etc...
By the end of it, the magic the closet took to maintain itself was like that of Three average wizards a day, and every store inside of it took another wizard's magic but Wonder Alley was ready to open.
With the time being summer vacation, and many children have parents working in Diagon Alley, and those that didn't often go with their parents shopping, it didn't take long before children started to flock into the door, and once they did, more and more came in.
Getting people to work for them was even easier, with the twins convincing their friends to work for the summer as a way to get money for themselves, and people coming to apply little by little for jobs, in two weeks they went from having four shops, in which two were for card dueling, one for snacks and the last one being a prank shop, to have a card dueling field where people can duel for free, a paid dueling field, where they can get advice how to improve a restaurant that has both muggle and magical food and drinks, and a cloths shop that made use of the Acromantulas' silk.
The best thing is that with them putting a couple of workers at the entry of Diagon Alley with flyers about Wonder Alley, not only did more and more wizards and witches heard about the shops and bought dueling disks and cards, but when the 11 years old muggleborns and their parents came to shop for Hogwarts for the first time, they stopped at Wonder Alley to buy clothes made from silk at cheap prices, and sometimes also bought the game for their children.
But, of course, for every positive there is negative, and with their influx of muggles and muggleborns, came the reaction of the purebloods and their lackeys.
They didn't stop shopping in the new Alley, why would they? Not only were they able to get cheep Acromantula silk cloths in here, but more then half were addicted to the feelings card dueling gave them, instead, the purebloods wanted the muggles and muggleborns gone, and the lackeys wanted a percentage of the money.
It started with a ministry worker coming first, talking about how it is forbidden to expand shops in Diagon Alley, and hinting that a few Galleons can make it go away.
Of course, it was then explained to everyone that Wonder Alley is inside a closet that was expanded and that there is no laws forbidding it.
After which there were a few tries by the minister to pass a law that make you need to pay to do something like that but it never passed with the help of Voldemort telling his followers to stop it because Harry told him, and surprisingly Dumbledore saying the same thing to his followers as Remus and Professor Snape shared.
After which there were a few tries to cause havoc and destruction either inside Wonder Alley or to it from outside, non were successful and were dealt with by stunning the ones that did it and forbidding them from ever coming back before calling the Aurors.
All in all, it took till a week before the start of the school year for everything about Wonder Alley to calm down.
As Harry is a secret partner, the twins were the ones that dealt with most of those things.
Harry instead gave a few advices and worked on his own things.
In regard to the Death Eaters, other then make Voldemort tell them to play card dueling as a way to train their mind to react to different situations, and to prevent the destruction of Wonder Alley as 'it would be a great place to make a statement and kill those mudbloods!' He only told them to focus on retrieving the prophecy from the ministry, something that as the books made clear, was taking time.
Both Remus and Snape kept informing him about the Order and all the things it didn't do. Seriously, waiting patiently while trying to prevent Voldemort from getting the prophecy instead of just destroying it? Reaching out to Giants and werewolves and ask them to not take Voldemort's side without promising any benefit? It is like they want Voldemort to win.
All of the above weren't the things that took most of his time, what did was the Acromantulas, or more specifically, their fangs.
After making the four first shops, Harry spent two days creating an additional closet like Wander Alley, where he set the giant spiders loose, and by loose he meant gave them an order to make much silk as possible and put it in baskets, and cut off each other's fangs every few days as they grow back, and put it in different baskets.
While the silk went to be sold as cloths at a price that covered their food intake, their fangs were put into research about their properties and how to purify them, which, after researching it for over a month, reached completion.
The thing is, it isn't hard to completely purify magical ingredients like fangs, feathers or hair, but if you do so completely, they will lose their unique ability to strengthen a person's ability to the spiritual realm, if you want it to still have this ability, then the core needs to have a little of the same characters as the creatures it came from.
Which meant Dragon cores aren't loyal, instead they are searching for the strongest wizard they can get to 'mate' with, Phoenix cores are prideful and search wizards that have fame or want fame, and unicorn cores are loyal to the core, and search for pure hearts.
Olivander use those three because he managed to reach the perfect balance with them, they aren't rebellious, but their will isn't dead.
Harry went to a different direction, he had the Acromantulas' behavior changed already, they are now hard working, compliant beings that obey his orders, he only needed to clean the intent inside the magic in the fang that makes it grow by will and the knowledge that he is their master, and everyone could use it, though the second someone does it gets imprinted on him and can't be changed.
Finding the right amount of cleansing needed to a month and he finally had the chance to do the last thing he needed to do before summer ends.
The ritual with Nagini