You need to have an account on a Quassel core to use this app. If you have none, you can either set a core up yourself, or check if you can get an account on someone else’s core.
This app only works with cores that run at least Quassel v0.6
This app only works with cores that run at least Quassel v0.10
To learn about how to set up a quassel core, see the wiki.