Articles, grammar, selection

Hi all,
Sometimes I have problems with articles, that is, I don't know whether I should use 'a/an' or 'the'. I do know the grammatical rules but I can't recognise whether a noun is definite or not. Please have a look at the examples below and express your feelings (these are from rental agreement terms and conditions).

"The Rentee shall provide (a/the) finishing floor layer, adjusting the upper floor level to the finishing floor level in the publicly available parts." - "a" - meaning any finishg floor layer that meets certain conditions, or "the" - meaning layer in these certain premises?

"(-/the) ceilings should also provide access to all parts of the systems and devices that require servicing or adjustment" - the meaning of "ceilings" in this sentence is kind of generic, but generic only for the certain area, that is all ceilings in the premises in question that are or will be provided. These are not concrete since there may be no ceilings yet.

"Record the test results in (a/the) relevant report." - the word "relevant" seems to limit the scope of meaning, which suggest to use "the", because only some particular reports can be used, on the other hand, there may be a few relevant reports and the reader might have been given a free choice as to which report will be used.

How do you understand those sample sentences?
I would be very grateful for any suggestions.
Regards.