Use of 'kepeken'?

[janAetherStar]

Ok, so I never learnt what a preposition was at school or anything. Let me try to get this straight so I can make sure I don't mislead my friends who are learning tp.

kepeken on its own needs an e, but if you're using 'kepeken' to do a different verb you don't?
e.g.
mi kepeken e ilo moku = I use the fork (for whatever reason)
mi moku kepeken ilo moku = I eat using the fork, and thus you're using the fork to do a verb other than 'using' itself so you don't need 'e'

Is this correct or am I way off?

[janSilipu]

Correct and probably a useful way to put it.