The numbers do not matter. There are 3 outcomes for the first spinner and 6 outcomes for the second. 6x3 is 18. For each of the 3 outcomes for the first spinner there are 6 for the second.
The first spinner has 3 outcomes; the second spinner has 6 outcomes independent of the first spinner's outcome. In other words, what happens to the second spinner has nothing to do with the outcome of the second spinner. There are 3 x 6 = 18 possible outcomes for both spinners.
Here's a complete list of outcomes (see the attached image).