The rule for a 3-C point is simply stated:
Your cue ball must contact both other balls and it must make at least three "cushion contacts" before contacting the second ball for the first time.
There is nothing in that rule about what other contacts may occur during the shot or the order of ball contacts and cushion contacts other than "at least three cushions before the last ball". Also, it says nothing about using different cushions -- all the cushion contacts can come from a single rail for example with a masse/pique shot. Also, there is nothing in the rule about not hitting the first ball multiple times or the first ball not sending the second into motion before your cue ball hits it.
There is the small detail that if the cue ball bounces on the top of a cushion multiple times (and returns to the table), it counts as only a single cushion contact.
Some 3-C rule sets try to enumerate all the possible ball/cushion possibilities: 1ccc2, c1cc2, ccc12, ccc1c2, c1c1c2, ..... All of those are covered by the simple rule above.
If you are just starting 3C I urge you to get Robert Byrne's "Standard Book of Pool and Billiards". It has the best discussion in English of the game. If you find it useful, you may want to get his other two instructional books, "Advanced Technique" and "Wonderful World".
