Can i say
I have a lot of homework
Imam puno domace zadace
Imam puno domaceg zadatka?
Imam puno domać
ih zadat
aka (da uradim). (The Genitive case - I have
lots of - what?)
Imam neke domać
e zadatk
e da uradim. (The Accusative case - I have to do - what? Some tasks to complete at home)
domaceg zadatka is singular, so it can't go with puno, because puno is for plural (lots of, a lot of).
and for pravo and ravno could i use odmah?
on a website i say napisati for uraditi,raditi and napraviti.
Pravo kući* - straight home, like in English, shows ... again direction.
Odmah kući is I have to go home
right now. (stresses time dimension)
* kući (dativ) is from
kuća (house), but it means
home as well. I live in a flat, but I always say - Idem kući
napraviti is
to make. I don't know why Croatians say "to make homework" , I have to ask them

.
In Serbian it would mean something like "compose homework" for someone else to do it, not you to do it, or "to make some homework to do" , to give some tasks to be done (to someone) as homework
raditi - to do something
uraditi - to finish (doing) something, to make it done, to be done
Radim domaći - I'm doing my homework, or I do my homework
Uradila sam domaći (finished action) - I've done my homework