Placing stuff

This is going to sound stupid but I honestly can't figure it out. How do you place stuff in your room? I just got a room from my FC and some stuff to put in it but I've no idea how to do that. XD Any help is much appreciated! <3

Once inside the room you need to open the housing menu (Shift-H for me, although it's possible I made that binding myself a long time ago). On the menus it's under Social then Housing. Then you get another menu pop up, Indoor Furnishings is the top option and that's where you add, rotate, remove items.

Remodel Interior is the second option that will allow you to change the walls, floor and light fitting, but please be aware (if you weren't already) that once placed and confirm, you can't ever get the items back, you can only overwrite them. It's okay to put a wall/floor/light in to see how it looks, just don't press confirm, at that point it uses it.

Just to expand on what worldofneil said above, the part about not being to get items back is mainly for walls, floors, and the light fixture on the ceiling. There are some furniture pieces (like "The Unending Journey) that have this downside as well, but most don't, and the ones that do are labeled with the warning. Most furniture can be placed and picked up as often as you like, but once placed it is bound to the house and can no longer be traded to anyone unless they're a tenant of the house and pick it up themselves (although since you're talking about an FC room, you can put it in the FC chest and trade it that way).

There are also two small toggles on the placement menu, one allows you to snap movements and rotations to a grid, the other allows you to toggle whether or not a tabletop item attempts to position itself on a table/shelf or whether it ignores it as a potential surface.

Also, when viewing furniture in the furniture list, any piece that has a colored circle in the upper right corner can be dyed - just right click on it in the list and select the "dye" option.

Post pics when you're done! :)