Ah, OK.
To start with the database is called 'theocbase.sqlite' (exactly that), and the easiest way to find it is to click 'open database location' in Settings. You could send that file around, and other users would have to replace (!) their theocbase.sqlite files with yours.
In settings there is a 'Backup database' and 'restore database' function. This has caused issues in the past, but it seems to work all right now. Nevertheless: make a good backup of the original theocbase.sqlite file somewhere outside of the TB folder first. This backup function is easier to use: it creates a theocbase_backup.sqlite file for you to store where you like. You send it around, the others use the 'restore database' function and their existing database is overwritten.
Be aware though: if multiple users start changing things, it will soon be mess and you could be stuck with many different theocbase.sqlite files across a few computers. So you would probably need to agree that only one person performs changes. Or make very strict arrangements to make sure no one misses a change someone else makes (if that is possible at all)