I may have this in the wrong forum, and it may have been adequately
addressed in the theory forum, but this seems a simple question to
answer. To fianchetto a bishop, you simply move it to the first square
in front of the knight on the same side of the board. That is, to
fianchetto white's queenside bishop (the dark bishop) you would first
move the pawn on b2 (usu move it up 1), then move the bishop from
c1 to b2. Hope this helps.