Good choice on your first plane ! Multiplex makes great foam planes that can take a beating. The vertical stab will glue back on in no time!
I had a plane similar to this and most if not all pusher planes like this will tend to nose dive on hand launch. Having someone else launch it is the best bet here. To do it yourself you should get a neckstrap for the transmitter. Then hold the plane in your throwing hand and hold it as high as you can. With your other hand throttle up to full and steady the transmitter . Take a running 3-4 steps and sling it (throw/release) the plane out in front with a slight nose-up attitude. Then quickly get your hands on the elevator stick and give the plane a little up elevator....not a lot or it will stall and fall. . The trick is to quickly get ahold of the transmitter after throwing the plane. It takes practice to get the procedure down.
To launch it by taxing it on it's belly on the grass is another way and you found out what can happen there. The trick here is to make sure the grass is not too high and to get the plane moving while keeping it straight by using the rudder. Add throttle as it starts to slide ,keeping it straight with the rudder and then add some up elevator and it will rise. If you don't keep it straight and/or the grass is too high, a wing tip will catch the grass/ground and either spin the plane or flip it. Again this takes practice as welll.
The good thing with these planes is that the engine and prop is up high and will be more difficult to damage in a rough landing.
When you get better after more practice ,you can read-up on adding ailerons to the wing and really start having fun with it.
Good luck !