Hey Chris, welcome to Euroharmony.
Firstly, to get lined up I tend to use my GPS and also I find somewhere in my cockpit that if I get it lined up with the centre line I am dead on with the runway so I just line up this part of the cockpit with the runway and I am lined up.
Regarding speed and descent, try and go as slow as you can but above stall speed and I always try to aim for 1 red on the PAPI lights as when I put my throttles to idle the plane sinks quiet quickly and you will find that you will land early if you stick to the two reds. Descent wise, that can only be decided by you. This is the beauty with VFR, you fly the aircraft, no autopilot taking you down to the runway, if you want to fly 2000ft then nose dive over the threshold, you can, although I don't reccomend this :8
Just take it easy, don't go crazy with the joystick, make small slow movements and you will be fine!