I'm not sure from what you said whether you need intarsia or stranded knitting, but their is a free video on this site here
about each. Scroll down to "How to Knit with Two Colors". Intarsia is if you need to use quite big blocks of color, and stranded is if you are moving from one color to the other quite often. If you decide it is intarsia the main thing to remember is that when you switch the colors to pick the new color up from under the old color so that at the change it is caught up, if you don't do that you will have a hole at the changes. You also need to be working flat to do intarsia, there is a way to do it in the round, but I have never learned it and may not be where you would want to start with 2 color knitting. Another option is to knit all in one color or do the biggest blocks in intarsia and if there are small bits of the contrast color do go back and do them with duplicate stitch. Duplicate stitch is a kind of embroidery over the knit fabric that looks just like knitting. You can also do all the contrast color with duplicate stitch.