How can I remove these snap, crackle, and pop noises? [newbie]

The thuds at 1.155s & 3.777s sound like you blowing on the microphone.
They can be prevented by using a pop-shield.
( leave about a hand’s-width gap between the pop-shield & the microphone)

IMO there is excessive sibilance, (8kHz-12kHz), which is fixable in Audacity with a de-esser plugin.