Getting Started
Joining the server
If you haven't already added the server you can find out how to do that here. When you join you will find yourself in the lobby. You can either walk through the survival portal or right click the compass and click on survival.
Teleport away from spawn
When you first spawn in, you will spawn in the centre of town. Since you will be unable to break things at spawn unless you make a claim or have a certain amount of playtime you can teleport to a random place at the edge of spawn using /rtp. You can only use this command when you have the castaway rank.
Other useful things to know
If you get stuck in someone's claim you can use /trapped to escape.
You can claim your land so that it is protected from other players.
You can also link your bedrock account you your java edition account so that you have your inventory and progress on both platforms.
You can find all the other quality of life features here.