As you can see, the Farm is a lot larger then the one in Harvest Moon 1. The main area by the house is empty most of the time except for the Horse and your pet. To the right of the farmhouse are the animal barns. To the south of the farmhouse is the Secret Garden, where the flowers will bloom after you find the Power Berries. In the southeast corner is the Hot House, which in itself has two different entrances and is snuggled up against the wood bin where your wood is stored.
At the beginning the Sheep Barn and Hot House are not available. You have to have Ken build them for you. You can also not enter the Secret Garden; it's just there to show you how many berries you have uncovered at the current time.
Behind each Animal Shed is pastureland where you can plant grass. It is important to plant grass here because Chet determines if he can sell you animals by how much grass you have planted behind each barn. For example, Chet will allow you to buy a cow only after you have planted 6 plots of grass (FYI: one seed of grass will plant one 9-square plot of grass). If you want you can grow crops in the pastureland since there is a shipping bin in each one, but typically you want to reserve the land for grass.
South of the main farm area is the field where crops are grown. In the northwest corner of the field is the Shipping Bin. The Buyer comes by every day at 5 PM. If you put produce in the bin after 5 PM, the Buyer won't pick it up and it doesn't carry over to the next day. There is a stream running through the field and more land to hoe up on the other side. Ken can build you a bridge so you can reach the other side and plant your crops there.
To the west of the field is the fishing area and the Fish Pond. You can fish from here or fish in the stream in the field. Fish can either be put in the Fish Pond or placed in the Shipping bin for the Buyer to pick up.