Welcome to the site and welcome to dg. :hfive:
There are different approaches to the sport. Fore hand/side arm seem to be easier for new players as it has more of a pushing motion that a lil more natural for many. Throwing backhand, the natural tendency is to, well, throw it- the problem is that with bh, "throwing it" will get you nowhere besides in the bush on the left
bh involves using your hips to rotate your shoulders and using yor elbow as a catapult. Following through is one of the most important factors in any dg, or any sport throw.
When it comes to form, the faster you decide what you want from the sport the better off you'll be. You can have alot of fun, make alot of friends, and score better then a ton of the other players with bad form. Will you be able to compete with others that shoot the simillar scores- probally not as good form is more consistant. This applies to putting as well.
Certain choices, like lower weights and slower, neutral discs will promote good form. Reason is that for most to throw fast overstable discs, they have to force it- never getting it to it's proper cruise speed and seeing how the disc really flys. So what the problem with that if it's going as far as others? Nothing now- but later it will be harder to improve.
The most important thing is to have fun- seriously, as cheesy as it sounds. I personally find myself having way more fun winning
I went for two years without ever winning once( I was the only newb in the group )- now I'm outdriving them and putting more consistantly
now if I could only throw forehand