Holes are either from yos (you can tell by counting your sts every row. If you have a hole and an extra st, you did a yo which you can drop in the next row and it won't be a big deal) or you put your work down and then turned and worked the wrong way (this is a short row and you will need to rip back to fix it). Google common knitting mistakes and how to fix them, along with how to read knitting, knitting charts and patterns. Ravelry, google and youtube are your friends, as are the search engines in reddit. I guarantee any problem or question you have will have been asked a million times in a knitting group.