Ariadne gave you some very good tips. For exercises use your imagination and after you get a first feeling/impression of the class, the participants, their fitness level and first impressions you will have a better idea of how to continue with the rest of the class as well. Keep your mind open and always have alternative exercises for those participants who cannot perform a specific exercise/moves.
One routine out of the box which you can incorporate into your regimen, is to take the class for a walk or even a run/jog if they are up to it (carrying their bosu ball). Then every few minutes or a certain distance have them perform a number of exercises (either counting repetitions or for time) and when done move to a different location. Keep repeating this for the whole session. This will improve their stamina, burn calories, make it more exciting and fun and it will give them time for some active recovery between their exercises and their walk/jog.
I hope this helps. Good luck.
In terms of specific exercises that can be done with a bosu ball, it looks like you are a certified personal trainer, so it seems likely you are well up on your anatomy and ways to sequence exercises to target various muscles.
The difference with group ex, of course is that you have a lot of different people you need to modify“. not so much that one routine will fit all needs, but that each exercise has to be able to be modified.
I like to use a ladder“ take a base exercise, teach that one, and then do 2 or 3 more sets, each one with a slightly harder variation (how you do that depends on the exercise, sometimes I use a single limb, sometimes double, sometimes add resistance, sometimes add a core component“ I am sure you know the drill“ as people come regularly they know the blocks, or ladders“ and I invite the students as we go up the ladder either to go up a rung, or go down a rung as they need.
I find if you meet people eye to eye, ask before class if there are things they would like you to help them to find modifications for, and invite them to modify harder or easier of for their particular needs that is helpful. Most people are there wanting to like it, and your energy and connection to them is very helpful.
I think where you are is rather hot and humid, yes? Probably also helpful to remind them to hydrate, though you probably do that with your personal training as well.
I hope you enjoy your classes. Group ex can be a lot of fun.