Memory usage

Hello. Did I catch up with the use of memory? Use a common STACK for all the threads or each STACK sampling, as is the case with FreeRTOS? Thank you.

That library does not manage memory at all, as well as it does not manage any kind of context switch. It just schedules to run function callbacks at certain timeframe inside the main loop (or interrupt handler).
So the answer is - common stack for everything. Threads are not isolated from each other and from the other code.