The Amateur Draft usually takes place the first week of June. While you are playing through a season in Career Mode, go to your schedule and go to June 1st and sign off until this day. Once the game stops simming, from the menu, click Advance League. A couple days will pass and a popup will come up saying that the Amateur Draft is about to start and it will ask if you want to go to the draft, click Yes. The draft has 25 rounds and you have to play through all of them. Just keep picking the top guy on the list every time and the draft will be over in no time. You cannot skip to the end of the draft, you have to complete it yourself. Once you finish all 25 rounds and press to pass through the draft summary, the achievement will unlock.