Trills with accidentals above them

[megs22786]

Hello all, I really need some clarification on this..
I am playing a piece with several accidentals but I have no idea how to trill these!

For example, in a key signature of b flat, e flat, a flat and d flat, there is a c trill with a flat above it. So how do I trill this?

Also, same key signature an f sharp with a natural sign over it.

Finally, an A natural with a flat sign over it.

Any help would be greatly appreciated!!!

[Gandalfe]

An accidental over a trill sign is applied to the auxiliary note of the trill (the note above the main note written). The auxiliary note is usually one LETTER above the main. For example, if you have a written C, aux is D. The auxiliary, usually follows the key signature, or the immediate harmony of which it is in context. If there is to be any deviation from this it is usually written as an accidental above or beside the trill sign.