How to learn FreeSwitch as a beginner?

Question

FreeSWITCH

Hello everybody!

Task:
Learn how to install FreeSwitch, configure it, create simple dialplans.
(More specifically, you need to assemble a robot that will call, say, 2 numbers and play a certain audio file to them)

Issues:
I have not encountered telephony before, so I have no knowledge.

What has already been done to solve the problem:
1. I watched general training videos on YouTube and read about how SIP works, in general, I picked up a bit of fragmentary knowledge.
2. I searched and watched videos on installing FreeSwitch, I managed to roll it onto the VM (I installed it on debian 10)
3. I read about 50 pages of the book Anthony Minessale II - FreeSwitch 1.8 (2017) in translation via Google (periodically looked at the original, if a completely crooked translation was visible), stopped at the moment when, after setting up FS, it is proposed to make test calls through the default dialplan (I picked up a VM on a PC, I couldn’t make a test call from a VM to a PC, I used linphone)

Now I understand that there is no general understanding of how all this should work, I want to fix it.

Actually to the question:
Can someone advise what I specifically need to study (what specific books, maybe there is literature in Russian, or is there educational video content, I even consider courses) in order to solve my problem?

I would be very grateful for any feedback!