Basics

A great start up is to use the "Resources For Archers Creator" All the base archers are already extracted with all necessary files

This post contains all the base archers (including Alts and Secret) slipped into pieces. All the sprites, archerData, spriteData separated into files. And all files necessary to create an (the atlas.png, atlas.xml, archerData.xml, spriteData.xml)

Also, an already configured Atlas Creator (created by Terria) to easy create atlas for Archer Loader. This Atlas Creator is localized at 'CreateAtlas' in the zip.

Check this resources and a video how to use them here

All custom archers need a folder with the follow files: the atlas.png, atlas.xml, archerData.xml, spriteData.xml

you also can have, optionally, the menuAtlas.png, menuAtlas.xml, menuSpriteData.xml

In that case your folder will have the following files: archerData.xml, atlas.png, altas.xml, spriteData.xml, menuAtlas.png, menuAltas.xml and menuSpriteData.xml