Since I had a comment about yarn, I thought I would take a minute and briefly highlight some facts about crocheting/knitting yarns. It is so much fun to go to a store and just look and, of course, touch the various skeins of yarn that are on the shelves. There really is a little more thought needed when purchasing yarn especially for a pattern or project that you have in mind.
When you look at a skein of yarn, there should be a yarn symbol with a number in the center. Those numbers actually tell you the diameter or weight of the yarn and then you will find a number telling you the yardage/grams/ounces which is how much yarn is in that particular skein. So you pick up a skein of that luscious purple that you think will make a wonderful scarf and you read that it is a number 4/100 yards. So you are really purchasing a medium diameter or worsted weight yarn with 100 yards available for your use. The Standard Weight Guidelines is a great website to check out for all the industry standards used on the labels of various yarns. https://www.craftyarncouncil.com/standards/yarn-weight-system
A simple review of yarn categories and weights is this:
(0) is a LACE weight perfect for shawls or extra find projects
(1) is SUPER FINE fingering yarn mainly used for socks and/or baby items
(2) is FINE good for baby and sport yarn
(3) is LIGHT good as sport, light worsted for clothing
(4) is MEDIUM worsted weight for afghans and clothing
(5) BULKY for scarves, hats
(6) SUPER BULKY crafts, rugs
On the labels, you will find the company’s recommendations for what the yarn should be used for and what needle size to use. When just starting out, I would stick with the pattern recommendations for both needle size and yarn diameter/weight to help you get the correct finished size. Make sure you purchase enough skeins to complete your project using the yardage/gram information.
As you become more proficient, the needle size might be different based on how tight or loose your stitches are (which is called your gauge, a whole new blog) and you will find that you will either use a smaller size or larger size needle(s). Also, it can be very creative and fun to take a pattern and use a different yarn than what is suggested, the results can be very interesting. You just need to remember that when changing anything about a pattern, you will have to readjust your yardage amounts which means you will either need to buy more or less skeins of yarn. Of course, having left overs is always a plus for those small items just needing to be made.