There are two ways in: through the Kixa lobby, or straight to your server's own address.
Join through the Kixa lobby (Java)
In Minecraft Java, add the server play.kixa.host and join it.
Open the compass server selector in the lobby.
Choose your server. If it is asleep, choosing it starts it, and everyone waits in the lobby while it gets ready.
Your server only appears in the selector when Lobby listing is turned on in its Settings. Listing it also lets other players in the lobby find it, which is how new people discover your world.
Join your server directly
Every server gets its own address from its name: name.kixa.host. Share that address with friends who want to skip the lobby.
Bedrock players
On phones, tablets and Windows, Bedrock players can add bedrock.kixa.host to reach the lobby, or yourserver.kixa.host to go straight to your server. Consoles can't add servers yet.
If you only want Java players, you can turn Bedrock players off in Settings.
Common questions
Why can't my friends see my server in the lobby?
Turn on Lobby listing in your server's Settings. Unlisted servers don't appear in the compass selector.
My friend joined but the server isn't running
Free servers sleep when empty. Choosing the server in the lobby wakes it; players stay in the lobby while it starts.