vtiger72

Teams with six wins or less participate in the first lottery for the top supplemental draft picks. The team that posted the worst record among that group is given a weighted advantage over the following team, with each team's "weight" being decreased on down the line until reaching the team with the best record in the group.
The second group consists of non-playoff teams and follows the same weighted system.
The third group consists of last season's 12 playoff teams and, again, follows the same lottery system.
After the order is determined, each team submits to the league the name of the player(s) they are interested in, as well as the round of the supplemental draft they would like to choose them in. The team that submits the highest bid is awarded rights to the player. If more than one team bids a pick from the same round, the team with the highest pick in the round wins out.

If a team uses a pick in the Supplemental Draft, they must forfeit their choice in the corresponding round of the next years NFL Draft.

So, it's a blind draft. You decide which player you want and what round pick you are willing to use to get him. If you have the highest bid you get him but surrender that round pick in next year's draft.