Twist the first band into a figure eight or infinity shape.
Place it on the loom like so.
Take the band in your hook like this...
Twist it onto the third peg so it makes an 'A' shape of sorts.
Add a second ban over all tree pegs (untwisted).
Take the band in your hook...
Pull it over this peg...
And Into the middle.
Repeat on both other pegs.
Add another untwisted band.
Repeat the steps until you get the desired length.