Landscape Paint's, Dieing when you get to low and proper people

Hi! I’m developing a survival game and i need to reduce the depth before you die so people can go very low in the game. So far it isn’t working and its going to effect the game. I also cant paint the landscapes. I have tried the tutorials but they still aren’t working. Lastly i had to choose the first person shooter to get proper things like jumping and falling. I want to digure out how to make a full human like body with hands showing. I hope this isn’t a fat order and I hope you guys can help me