How to merge two audio inputs/outputs in GNU/Linux?

Question

linux

Good afternoon! I have Linux Lite 5.8 based on Ubuntu. I am recording video using SimpleScreenRecorder. In the sound settings, you can select the server, it costs PulseAudio, and the available options are ALSA and JACK. Well, each server has its own list of sound sources.
I need to record simultaneously the sound from the microphone and what the OS plays (sounds of browsers, games, programs).
How can this be done?

Answer 1

Here What is JACK or tu-ta JACK_Audio_Connection_Kit

Answer 2

You need to output both sounds to the "virtual" audio output and record from it in the program ... I won’t tell you the details, but there should be articles in Google