How to Create Lumps?

Hey, so I'm in the process of making Bean the Dynamite as my first character wad, and when reading on the wiki how to create characters, it needs a Lump named S_SKIN. I can't exactly figure out how exactly to add lumps on Slade, so any help with that, or making characters in general would be appreciated.

---------- Post added at 02:14 PM ---------- Previous post was at 01:29 PM ----------

Update: Nevermind, figured that out, but how would you name sprites that have multiple frames, like the running or spinning animations?

---------- Post added at 02:26 PM ---------- Previous post was at 02:14 PM ----------

Update 2: Nevermind, figured that out too. Just, any advice in general would be nice.

One: You don't really need the skid sprites, since all vanilla characters use their first walking sprite.
Two: Try to choose an ability that fits your character. For example, a hedgehog that can fly with his hands isn't really logical.
This applies to secondary abilities and flags too.
Three: Make sure the character can complete every vanilla level.
Four: Character sprites have to be colored the default green (colors 96-111) in order to use color-changing features.
Five: Animations should be logically correct. If the character has details that only exist on one side, don't mirror the sprites.