The gauge is not important.

When you carry the yarn up (it is a bit like intarsia), drop the yarn about to be used under the yarn you have just used. This, of course, is not necessary for the first time you use your #2 colored yarn. Be careful when you weave in the end for this first use of a yarn: do it in such a way that you don’t leave a hole.

You can conceivably make a rainbow type arrangement of colors or a range of the same color. It’s your ‘canvas.’ Feel free to do what you want in terms of color.

The puffy ridges are the result of the purl rows jutting out. Stockinette rows have a tendency to fall back into the fabric.