It’s a complicated topic, so you must do some reading on your own. So search the forum and read bubble docs.
But in summary and my current understanding:
Max capacity is when you used out all the server space you have on your plan (personal in your case). Which means that some operations could be scheduled +1,2 sec in the future when the more capacity will be available - it happens if you have reached 100% of your available capacity.
Average CPU is just this the average of the strain you put on your slice of the server in chosen time frame. It depends on how heavy your pages and your workflows are.
++ in my experience using your test mode and refreshing you page every 10 sec put much more (3-4x) strain on the server than normal user on the live version - you can test it yourself what is it in your case.
Lets say average user per space in time (2-3 seconds) uses 1% on your personal plan - that means you can have 100 concurrent user’s doing sth (loading page, triggering the workflows at the same second (or two- not sure what the window is here). But there are apps that have 100s of users and personal plan is enough.
If on another plan you have e.g. 5x the capacity than on your personal plan - you can sustain 500 users (of course if your user uses 1% but it’s more likely 3-5% depending on the heaviness of his actions (page load, workflows etc)
Of course that is my understanding
well if 10k users do sth on your page in the same second - you will have a problem. But 99,9999999999% of the apps will never get to that point. So don’t worry about it and try to get first 100 users