There are multiple, correct ways of saying these sentences, and its difficult to choose the correct words and is something that native English speakers spend time on when writing about their experience. Different people will have different opinions on which words to use, but again, there are a variety of ways to write about experience. What your wrote is fine but take a look below for ideas:
* to advise students/future students on how to apply and begin university.
OR, what your wrote is fine: to advise students/future students how to enter the university.
* "I have been consulting/advising..." this is fine, but another way could be:
I have been consulting/advising students/entrants on higher education in (state), on obtaining a university degree...
* Assisting with documentation and application process (this is fine, however, you can add the word 'the' before the word 'application' if you like. (Assisting with documentation and the application process).
I hope this helps.