yes the trigger is the final maturation boost and causes you to release ALL eggs from that cycle.
without it a single egg will become dominant and ONLY that ONE egg will release unless you are lucky enough to get fraternal twins on your own.
they are all just generic names for basically the same thing some are more popular than others thats all.
there are many doses but the everage for ovulation is either 5k or 10k if you are on the lighter side you may be fine with a 5k but most of us here opt for the full dose of 10k
the trigger is best when given with a positive opk some women feel comfortable enough with knowing their own body to do it sooner but you do run the risk of ovulating immature eggs and wasting the cycle. so be SURE of your body if you do trigger without a positive. most will say tho if you dont have a positive by CD16 then go ahead and trigger because you dont want your eggs to overripen.
I had major side effects after my triggers. not everyone does. I cramped and had sharp pains for about 36plus hours the next day hurt to stand up straight. not all get that bad. you can get nauseous, frequent urination, basically any pregnancy symptoms.
Hope I got them all