If they're not collecting the corpse, there might be a few reasons why.
- Check that someone has the burial labour enabled. They all should by default, but I don't know what you've been messing with.
- It's possible in the orders menu (o) & forbid sub-menu (shift+f) to automatically have dead dwarves forbidden. It should be off by default, but if you've turned it on you may have to manually reclaim the body - either by looking (l) at the corpse and claiming it (f), or designating the whole tile to be claimed (d)(b)(c).
- Sometimes dead dwarves tumble into unreachable places, like rivers. You may not be able to recover the body unless you build pumps and stuff to get the water out.
If you can't recover the body, you might need this:
If there's something strange and it don't look good, you can always use a memorial slab instead of a coffin. Slabs are a little more complicated, but not completely unintuitive. Here's how to use them:
- You build a slab at a mason's shop in the same way you build a coffin. The slab shortcut is (alt+s).
- Before you place it you need to engrave it with the correct name at a craftsdwarf shop. You need a dwarf with the stone detailing labour to do this, despite the shop. The engrave slab shortcut is also (alt+s), after which you pick the name from a list of dead dwarves.
- You build the slab and place it wherever. This shortcut is also (alt+s).
Note: If you have more than one slab, the list won't show you which is the engraved one. To see more details in the slab list, press (x) to expand the list. This should show individual slabs and whether they have names. This is also useful for placing specific statues as decorations, or making sure furniture is of the right quality.