So you want to make your own bot on mazie.rocks (not Matrix Link)?
Follow instructions here
After running the command link user your.token-here, a new puppet ID will be created. Remember your ID because you will need it in every command.
You will be able to invite your bot to Discord servers, and then bridge them using the bridgeguild command. Once it is bridged, you can invite yourself to channels (see steps here). Only you will be able to use this bridged room.
If you want to allow everyone on mazie.rocks to join, set your puppet type to relay:
settype [puppet ID] relay
Another fun feature is that Discord users can DM your bot and you will receive these DMs on Matrix.
If you want to bridge your ACTUAL DISCORD ACCOUNT (not bot), this is possible, but keep in mind that Discord does not allow logging in with third-party clients, so if you do this, you are technically breaking Discord terms of service
Follow instructions here to get your Discord Token. If that doesn't work, try this.
When you know the token, follow the steps for bot (everything is the same).