Welcome to Kaighver

Here's how it'll work:
You can create a topic or join a topic someone has already posted.
Once you've joined in on that topic, that is THE ONLY ONE YOU CAN POST IN. You may not post in more than one topic at once.
In order to move to another topic, you must have your character leave the current plot line of the topic you are in.

When a topic's plot line has runs its course, that topic will be locked and no more posts in it will be allowed. Example: you start a topic to start a quest, and then when you finish that quest is when the topic's plot line has finished and it will be locked.

After that happens, you can create a new topic or join another topic that is just getting started.
If in a topic the characters already have a quest underway and they're far into it, you MAY NOT jump in.
If they haven't left yet, or just left and haven't encountered anything yet, you may join.
Whoever created the topic has a say in who joins and who doesn't since they are treated as the party leader. In online games where you can form parties, the leader is the one who can decide, so the same applies here.

When creating a topic, you MUST have a game mod for controlling NPCs and enemies. More than one mod may take on a topic. BUT YOU HAVE TO HAVE A GAME MOD THERE FOR YOUR TOPIC OR ELSE YOU CAN'T START YOUR QUEST.

If you have anymore questions about this, ask them in the questions topic located under "Game Information".