Anyone know how to craft a bed in terraria?

Spider nests are the place for cobwebs, the underground areas where the background wall is covered in web. You'll clear a few stacks in a couple of minutes. If you click the bed and the spawn point doesn't set, the room usually doesn't count as a proper house. Open the housing menu in your inventory and check that room - it'll tell you what's missing.

15 wood and 5 silk at a sawmill. the silk is the annoying part, you make it at a loom from cobwebs (7 per silk), and cobwebs are everywhere in the underground caves. sawmill itself is made at a work bench. place the bed and right-click it to set spawn.