You will need the following:
A can (or more) of plastidip
Some sort of rag or paper towel
Some type of cleaner/degreaser
Newspaper, and painters tape (optional)
Your part that you wish to dip.
Step 2: Clean!
Use the cleaner and rag to get all the junk off of your whatever part it is that your dipping. Clean it really good, that way the end result will be better.
Step 3: Now The Fun Part!
Ok, so now that your part is dirt-free, you can begin to paint.
Shake the can vigorously for a couple min to get the dip all mixed up. If its cold outside you may want to heat up the can with a hairdryer or something. This helps the spray pattern of the dip to be more of a fine "mist" rather than globs.
Your first coat should be very light (you should be able to see about a 50% transparency.
Wait about 10min after your first coat, then go for a second coat. This can be a heavier coat than the first. Repeat until you have a solid 4-5 coats. (The more coats = easier to remove later)
And your done! :D
Wait about 15-30 min before you put the part back on your car.
Step 4: Done!
Step back, and take a moment to appreciate your hard work.