How a roster is assembled
A captain invites a player who already has an A.C.E account. There is no public share link, and a Steam password is never asked for.
This page explains the written ladder. It does not apply a match, and it does not change a stored rating.
The invite that exists
On the teams page, a signed-in captain pastes a SteamID64 or an A.C.E account ID. The account must already be linked through Steam OpenID. The server writes a pending invitation when the database accepts it.
The roster holds five players, including the captain. A captain cannot invite their own account. A player who is already on the roster is refused. If the database is down, the invite fails and no invitation is stored.
What an invite is not
The invite does not mail a letter, open a private lobby, or generate a link you can post. It does not place the clan in the knockout.
The knockout code allows two named substitutes once a tournament entry exists. Entry is not open, so those seats are not a pass you can use today.