I don't have many resources related to Microcontrollers or Microcomputers, but here's a few (just remember you need a Raspberry Pi, Micro:bit, or an Arduino to do these)
Micro:bit Classroom (Microcontroller)
Arduino Courses (Microcontroller)
RaspberryPi Course (Microcomputer) - Getting Started with your Raspberry Pi
Differences
Microcontroller: A small computer used to control electronics (could not act as a standalone computer)
Microcomputer: A small computer that can act as a less powerful computer (could act as a standalone computer, but wouldn't have the same processing speeds/capabilities as a desktop PC) - probably comparable to 1990's computers in terms of processing capabilites.