I see terms are being brought up, this is simple. A motor is electric and an engine is internal combustion. The angle is the thrust angle. Not all planes require it. It isn't the same for every plane. Some kits and ARFs come with a built in thrust angle. I set up my own planes with zero thrust angle then during my trim flight testing the plane shows me what it requires. I think in the classic pattern forum you can locate instructions on flight trim testing. It's not hard to do. If you don't have any thrust in your plane it isn't going to crash. You can still trim the plane for straight and level flight with your radio trims then when you get home you can add thrust if needed. It's usually only about 2 degrees and can be right thrust and/or down thrust. The CG is perhaps the most important thing. If that's off and the plane is tail heavy then your first flight may be your last.
Doesn't sound like you have flown before so you should get with someone that knows how to fly to do your trim for you and maybe teach you how or at least go over your plane with you.