Skins and models are seperate, and its not always any editor is capable of skinning/modelling.
Skins - You do not create skins. You edit (skin") a existing texture skin with a image editing program. Try out GIMP, a free image editing program. Remember to be patient and practice with the image editing program, do not rush or start whining...
Models - You will need a modeling program. Much more complex than skins. Ask for help in the models forum.