CBT:
Classroom stuff: road positioning, basic laws, protection etc, etc.
Outdoor, closed road: shown around the bike (controls etc), moving the bike around (walking), placing on/taking off stands, clutch/gearbox stuff, basic manouvering (fig. 8, turning etc), emergency stops, observation exercises (lifesavers etc).
Outdoor, open road: radio link to CBT instructor, put into practice everything covered.
If deemed satisfactory, you’re issued with a CBT certificate (DL196). If deemed unsatisfactory, you’re asked to come back for another go (sometimes FOC, depends upon the school). Note there is no “test” as such, just showing you can do everything you’ve been taught.
It’s not “hard”. It seems like there’s a lot to take in, but it’s not that bad. Just listen to what they say, use your head and enjoy yourself. Do that and you’ll be fine.