First You Need To Create A SMD/DMX for example i use blender to create that
Second You Need To Create A Backpack Icon For Your Hat/Misc
Third You Need To Create Textures For Red Blue Or Single Only
Fourth Depending On Creating Your SMD/DMX if it's 1000 or more you need to enter in a medium lod if the medium lod is to big then you need to make a small lod
Fifth if you make a hat or misc the way to bone it to a bone in blender is click on a little circle which is a bone go into pose mode select the bone again then drag (YOUR HAT/MISC) to clear parent and drag it back to scout with the bone still selected drop it to (CHARACTOR) then click bone and it's boned
Workshop
First thing is select on top if it's hat or misc and leave the bodypart to head then you click on a charactor choose a lod and uncheck on the left of lods and on the right of charactors it should say bodygroups in it uncheck the stuff you want to be invisible and check stuff you need it to be visible now select the backpack icon and select in textures if you want it to be all teams or seperate and select the textures now click verify to see if it's done and if it is with no errors click finish after importing select a workshop picture put in name and description click ok and theres your workshop file thanks bye