You need to complete a few steps to bring the Able Sisters clothing store to your island. This is all that needs to be done.
1. Upgrade the tent to the house
If you can develop your own island a bit, you can only let Able Sisters open a store. It all starts with upgrading the tent.
2. Bring 5 small animals to Tom Nook
The next step in developing the island includes building a museum. In order to attract Blathers and its museum to your island, you need to bring five ACNH Nook Miles Tickets or fish to Tom Nook at the permanent service center. After receiving the fifth critter, he will call Blathers. Upon completion, he will inform you that Blathers will appear on the island the next morning and will ask you to choose the location of the Blathers tent. Scout around your island and choose a good place for your tent. Eventually, it will become a museum.
3. Build a museum
The next morning, you will find an owl in the tent. Blathers is keen to build a permanent showroom for the small animals on the island. You need to bring 15 new small animals or fossils to achieve this goal. After finding enough things, give them to him. You will be notified that the museum will be under construction and will open the next day.
4. Build cracks in corners
Go to the Resident Services Office and talk to Timmy and Tommy Nook. They will tell you that they want to open a new store called Nook's Cranny and need your help to achieve this goal. Run around and collect the following materials for them: 30 wood, 30 hardwood, 30 softwood, and 30 iron blocks.
After collecting all the content, please convert the material to Timmy in the permanent service department. Then it's time to choose the future location of Nook's Cranny store. Choose the ideal location that suits your island layout. The next morning, construction will begin. The next day, the store will open.
5. Buy some clothes from Mabel
Please pay more attention when Mable puts clothes on the square. After she arrives, she needs to Buy ACNH Nook Miles Tickets from her. It took a certain number of bells to wear a certain amount of clothes to make her want to open a shop. However, either way, some money must be spent on her products. It is recommended to buy at least five items and spend at least 5,000 bells. Depending on the funds you have, you must wait for her to visit your island several times before you can achieve this goal.
6. Choose the location of the Able Sisters store
The next time Mable shows up on your island, she will express her interest in establishing a permanent store and will provide you with an architectural drawing kit. Find the ideal location for the store and set up the drawing kit. The next day, the store will start construction and open.