Hey there
You pretty much got it.
Nari = eye
si = something that you often see after a noun that makes it a verb, kinda means "do"
Srung = help/assistance
srung si = to do assistance / help
Tìkangkem = (the) work
tìkangkem si = to do work
Nari si is kind of idiomatic. To do an eye. Or Eye as a verb. It kind of has the meaning look out / watch out / be careful.
Hey it's cool if you Na'vi speaking isn't where you like it to be. It's about playing around with the language, getting a feel for it and using it and having fun with it.

Hey you're a translator! That may help you on your quest to master the Na'vi language.. which by comparison to most natural Earth languages is very simple and straightforward.
All good things come to those who can wait... Hmm.. Literally, that would be something like: Fra'u asìltsan za'u ne fo a tsun pivey. (use an English word order on purpose to make it easier) I'm not sure what a very uniquely Na'vi way to say this is.