This achievement can be gain early in game as soon as you arrive in Whiterun. Go where the big tree is and close to it is the Jorrvaskr
(the companions main base). Enter inside and talk to Skjor about joining the Companions or you can just skip him and go downstairs to Jorrvaskr Living Quarters
and talk to Kodlak Whitemane
.Then the quest Take up Arms
Follow Vilkas outside, hit him with your weapon when he tells you and then you pass his test, he will give you a sword to give Eorlund
,so go give it and after the conversation you will have with Eorlund
he will ask for a favor to give Aela
her shield back. Accept and go give her the shield.After a small chat you will follow Farkas
to your quarters and thus the quest ends giving you the achievement.
Good luck and enjoy Skyrim on the One.