copy down the rhythm, and finish it by adding notes and rests to complete the last two measures. Be sure to continue with the accurate number of beats per measure, and use at least one rest and a variety of notes in each measure.

Just practice. i used to practice whenever i could when i was younger because i loved it but i wasn’t the best at it. watch videos if you can, and any other tutorials.

Generally spontaneous human combustion is something that still bewilders some, human combustion happens very rarely and doesn't affect the surrounding areas, so unless you want to set your self on fire, human combustion will remain spontaneous and very rare.