Getting started with QOS?

Asterisk newbie here. Is there documentation somewhere devoted to QOS and troubleshooting audio quality problems? We are sometimes having poor quality conversations with audio drops and “bing” sounds. I have years of IT experience but not with Asterisk, QOS, network latency or those kinds of things.

my experience qos is done on the router side yealink default qos 46 26 look at this https://support.goto.com/connect/help/how-do-i-configure-qos-settings-gotoconnect-configure-qos-settings

Asterisk can specify QOS codes, but they are simply hints to the router.