The game is being developed with a "coop with friends" model, which can also be played solo.

What this means is that it is not intended for "random" people to be able to simply enter other people's game, without being invited.... As such, each time a new world is made by a player, it is actually locked against all others from joining it. If a player wants to invite others to play on his / her / their map, they have to create a password, then share that password with whomever they invite... It is assumed those others will be friends or people the player trusts.

The reason it is not just "open" to be able to randomly join any game is because there are almost no real anti-grief measures in the game to stop / deter griefers from causing trouble.

PVP , which this game calls "friendly fire", is disabled (by default), and can only be toggled by each individual in their own inventory screens... This means that players can't run around killing each other unless all parties agreed to it and each one toggles the button to activate the friendly fire.

If you want to join up and play with others, you will need to go to "Looking for group" sub-forum (linked above), or join Discord and find other players that way.

Good Luck