How to edit characters to new ones

[F1rst16]

How can I edit the low poly crapy (JK) characters. I can do it with guns but how can I change the characters to my own.just the model. not animation yeat...

You wouldn't come around animating it after modifications have been done completetly from scratch, because the supported .md2 and .md3 model formats have frame animations...

Yea I was trying to do something by testing it out, like I just took the players chest and moved it out we-rd just as a test. Then in the game the characters body is all brocken up as in his chest was missing and stuff.Then I tried exporting as .md3 then it worked but no animation in the game. In my program the animations import as shape keys, as in animation in edit mode. vertexes and face select mode and stuff like that.