best 5 starting legends for beginners?

For begginers, I'd say the best role is jungler.
You dont have to be worried about a unfair match up, last hitting, warding... That's advanced.
In jungle you only have to kill monsters, gank and smite objetives. That's only the beginning.
I started Warwick on the jungle. It's pretty easy: you'll never die vs the monsters.
Then I played Udyr. Easy as well.
After that you can try other champions which easily clear camps: shyvana, amumu, nunu...

For laners:
Top: Teemo, Poppy, Renekton
Mid: Malzahar, Diana, Lux, Orianna
Adc: Miss Fortune, Caitlyn, Ezreal
Support: Janna, Lulu, Morgana (tho it depends on your playstyle: aggressive, tanky, shields...)