After selecting a house, you'll be asked to visit Tom Nook's shop as a part-time employee. This is mandatory for paying off your debt, and it serves as the game's tutorial. Use the map at the train station or the police station to find the shop. Its symbol is a red house, and it is always found in row A. Go to the shop and enter the door to start up a conversation with Tom Nook.
He will give you a work uniform. Use or to bring up your inventory, and put on the work uniform. Talk to Nook to get your first task.
Task 1: Plant flowers around the shop
You will be given several flower seeds and saplings to plant around Nook's shop. To plant something, stand on an empty space of land, open your inventory, and select a packet of flower seeds or a sapling. You don't need to plant them around Nook's shop; anywhere in the town will do. Once finished, go back to the shop and talk to Nook for 80 Bells.
Task 2: Meet villagers
Your second task is to introduce yourself to all of your neighbors. If you are in a newly-created town, there will be six of them. You can find where they live on the map; look for the small blue and purple house symbols. The houses in acre B-3 are for human residents, so you don't need to check those. Animals will usually be wandering outside their house, but they may also be inside. Go up to a door and press to see if an animal is inside or not. You do not need to talk to any animals inside landmarks (such as the police station or the museum).
You also need to talk to Tortimer, the town mayor, who can be found at the wishing well (signified by a red fountain on the map). If you think you've met everyone, go back to the shop and talk to Nook. He'll give you your next job if you have.
Note: You can accomplish this task prior to your first one, as all the residents you're required to meet will be active after you purchase your house.
Task 3: Deliver furniture
You will receive a piece of furniture to be delivered to a random animal in town. If you forget, talk to Nook again or check the item in your inventory. Find and talk to the animal, then say "Delivery!" Select the furniture to give it to him or her, and you'll receive a piece of furniture in return. Return to Nook's shop to earn 230 Bells.
Task 4: Send a letter
Nook will give you a piece of stationery to write a letter to a specific villager. To write the letter, open your inventory, select the stationery, and select, "Write a letter." According to Nook, the letter should be a sales pitch, but you can write whatever you want. Once you're finished, go to the post office (look for the red envelope symbol in row A on the map) and tell the pelican to send the letter to the villager. Go back to Nook's shop and he'll give you 130 Bells. If you lose the stationery along the way, return to Nook and he will give you another one.
Task 5: Help villagers
Your next task is to help out some of the animals in the village by doing jobs for them. Talk to an animal and select the first dialog option. The jobs vary in time and difficulty, but most require you to deliver or retrieve an item. After completing each job, you'll be rewarded with furniture, clothing, wallpaper, carpeting, Bells, or stationery.
You can do as many jobs as you like. After you've completed at least one job, go back to Nook's shop and he will have your next task ready.
Task 6: Deliver carpeting
Nook will give you some carpeting to deliver to a villager. Once you've successfully delivered it, you will receive a new carpet for your house. Go back to Nook's to receive a reward of 580 Bells.
Task 7: Deliver an axe
Nook will ask you to give an axe to the same villager you sent a letter to for your fourth task. Complete the delivery, and return to Nook for 230 Bells.
Task 8: Post on the bulletin board
For your final task, you will be asked to go to the bulletin board in acre B-3 and post an advertisement for Nook's shop. It doesn't matter what you write. Once you're done, go back to Nook's.
After the eighth task, a small part of your first debt will have been paid off, and you'll be free to do whatever you want. You can return to Nook's shop to buy or sell items, and you can pay off the rest of your debt at the post office.