For some daily fantasy sports contests, if you didn't submit a lineup prior to contest lock, your entry will be given a score of 0.
If you have not drafted your initial lineup for a specifically marked late-draftable contest prior to contest lock, you will still be able to do so! However, you will only be able to pick from players who have not started their game yet. You will no longer be able to draft an initial lineup once there are less than 2 remaining competitions in the slate that have not yet locked.
Additionally, some sports offer a late swap option, where you can change and edit your initial lineup as many times as you want before the start of the contest. You can also edit and swap any player up until they start their individual game.