How do I do the following

[Dylanblitz]

How do i change the music and the level name of a certain type of level with slade 3?

[Fonze]

Both can be different depending on what port and compatibility you are targeting.

Changing the music is as easy as (vanilla/Boom) changing the song's name in Slade to one on these lists, corresponding with the iWad and map number your level replaces. Alternatively, in zDoom you can use the MAPINFO lump to define level tracks.

Changing the map name gets a bit more complicated depending on port/compat. In zDoom, things are fairly easy; simply use the MAPINFO lump. In vanilla/Boom, DeHackEd is necessary. Don't ever change the map's lump name, except to ExMx or MAPxx.