Started mass effect 1 . terribly confused about what to do
Weapon selection is also confusing .
Any tips for understanding the environment ?
read controls and journal first. It has an inventory , level up system. Kill foes , get experience to level up your skills, talk to npc for more and more side quests. There are merchants also. You can grab weapons and armour throughout , go to inventory check which is superior have it , sell left things.
Also a personality/morality system is there, you may chose appropriate dialogues which decides what morals your character has and what his behaviour. This morality system gives you conversation skill , persuading , intimidating etc....
The more time you play , the more you get ease to it.