Learn from my mistakes
Touch up paint is fairly scary but easy with enough patient and balls.
I tried to sand, prime, base coat and clear coat a lot of little dings around my car. Afterwards, I realized that the directions the touch up paint had given me were just not even close to accurate and lacked many important details that they figured I already knew.
1. You really notice paint that doesn't have clear coat.
2. You really really notice clear coat that is higher or lower than the surrounding paint.
3. Paint overage is really easy to remove with wet sanding and patience.
4. It will take several days to complete, and many hours of labor and could end in disappointment or excitement. At least you can try and if you fail have them repair it.
5. One thin coat of base and clear might make you happy with little effort. It won't look perfect, but it will match much better.
6. Swirl remover and an orbital polisher are your best friend.
7. When a car is wet, you don't see scratches in the finish and think that you are the bomb, later when it air dries, you cry. But no worries, that is what #6 is for.
A rough list of the things you would need to do a perfect pro job:
touchup paint kit with primer, base coat, clear coat (don't get the pens, you will tear your hair out)
lots of tiny brushes with very small tips (the touchup bottle brushes are just too big),
a sand paper kit (220, 500, 1000, 1500, 2000),
and if you want to save your arms later, an orbital polisher with orange cutting pads and a swirl remover polishing compound,
Important take aways, less is more. Always use very thin even coats with plenty of drying time. Take your time, and don't worry if you scratch the good paint surrounding the area with the sand paper. Light scratches that your fingernail barely catches can be removed by the swirl remover compound and cutting pad with no paint work at all.
I would post a massive step by step list but it would take me hours and probably miss something. Look at some other instructions out there. At least, you know that the repaint of the bumper is always an option, and knowing how to do this will save you lots of money in the future when new door dings or hood chips appear.