newpic, I don't frequently give out "me toos", but you could pay hundreds of (insert local currency) and get no finer training than
SNS3Guppy has delivered.
The only thing I'll add is that crossbleed may supply more air pressure than an APU or GPU, meaning that after the first engine is started, the remaining one(s) may start faster and cooler. The corollary to this is that if you know one engine habitually starts fast & cool, start it first (SOP permitting, of course) then use it as a crossbleed source.
