I've seen many many guitars, and I've never seen or heard of a guitar that doesn't have what Kay described. The holes at the end of the strap push over the nobs on the guitar and stay in place.

For length, as long as it's a normal strap (nothing for a kiddo) you can adjust your length. You can have it really low for rocking out and trying to look uber cool, or higher up to play a slower more serious song, etc.

Guitars are wonderful, we have several all varying in electric, bass, and acoustic. Have fun!!