my first question would be why turbosquid?? makes the second why expensive? lol

ok what error are u getting from DS is lots of reasons it wont work and the answer would be different depending on the error

much the same applies to adding mats, is the model split up for diff mats or do you want to add new mats?? is it uv mapped?? and lastly how well do you know blender?? if its the first time you have used it I would sugest an hour or two of basic tuts, that should help you sort out the probs yourself or ask the right questions to get help