Im a new wow player, help

Hi guys, im relatively new to wow, with only 1 level 20 account used on the wow starter addition. I started using warmane today on icecrown because of the levelling xp and ability to go past level 20. I have a couple of questions which i know will sound very stupid to experienced players. How do i chose a spec? Im level 13 after playing for an hour and i cant pick a spec, i just have abilities to add to my action bar. Also, are abilities only learnt through payment through the class vendor or can you get them by levelling up naturally. I want to be an elemental shaman. Thanks all