Briefly...
If your music is all written in the treble clef: it has been transposed and all you have to do is play what you see.
If much of your music is in the bass clef: it has not been transposed. You will need to transpose it up an octave and a tone. And if the part includes chord symbols, you need to transpose them up a tone.
If your part is in A, any non-transposing instruments will be in G.
You might find the expressions "concert pitch" and "guitar part" useful.
"Music in A major for tenor sax" exists, but "Music for tenor sax in A major" doesn't. There's no such thing as a tenor sax in A major.