This is basically boxing with the addition of the 4 primary karate kicks:
front kick - mygeri
Round kick - mawashigeri
Side Kick - kekome
Back kick - ushiro geri
These are learnt on the shield and primarily delivered to the stomach.
Head kicks are secondary and you don't have to learn them unless you want to.
Other secondary kicks include the hook kick, done to the head, and jump kicks.
Practice is progressive:
ABCs:
Hand, hand
Hand, Foot
Foot, hand
Foot, foot
There are of course defences for the kicks and defensive combinations.
Then there is progressive sparring:
Boxing v boxing
Boxing v kickboxing
Kickboxing v kb
Then isolation sparring:
Lead hand only
Lead hand and leg only
LH and LL against kb
...etc