Q1 - How do I choose the hands?
A - I assume you mean the hands with the guns? Just go to files\gamecore\guns\model pack 5, pick the fists that you want, open that folder then copy hand_tex over the hand_tex in any of the model pack 5 guns' folders.
Q2 - How do I change the sky outside?
A - When you press build game, goto level settings, then press the global script edit button, under the tab 'level setup', there is a text box called sky, click on the text box with the filename eg. skybank\ww2\cty, then press the button with 3 dots on it and choose your sky
so what's the job?