It is best if you only as a question in one place.
To test the hose for air leaks: start with a dry hose out of the pool, hold the two ends up and fill the hose with water (being careful to not overflow), then look for water leaks. You can lower one end at a time to check for leaks near the fixed end(s), since it is simpler if you don't fill it up completely. Expect the swivel end, if you have one, to leak a little around the swivel joint (which doesn't matter as that end will be underwater in use).