Search for player by username?

Sorry if this question was answered elsewhere, but I couldn't seem to find anything about it on the forums. Is there some way to search for players by username? Reason being, I used an external application form so my players would have an easier time applying for the game and setting up their character. I asked for their roll20 username, thinking this would be enough to invite them into the game. But I can't PM them the join link since I'm not sure how to find their player profile. I thought for sure the player directory would allow me to search for players by username, but it seems I can only search by system, not username. Am I missing something really obvious here?

You can private message people if you know the username. 1) Go to your name at the top right corner of this page and click on it. 2) Click on Private Messages 3) Click on New Private Message 4) Type in the recipient(s) name and, if there are multiple users, select the appropriate user.

Ah of course! Really should have checked there first. Thanks!