Welcome! I have done one of these in a bit, thought it'd be fun to walk through the very enjoyable, always fun, granny square! Great for beginners, was actually the first thing I made into a blanket and is so versatile and beautiful. My granny square uses the Double Crochet stitch, will I will refer to as 'dc' in the below, and the chain stitch, referred to as 'ch.'
1. Chain 3. (you can also create a magic ring and do all the next steps, but this is the first way I learned to do it.)
2. Making your first double crochet: yarn over, insert hook in the third loop from the hook, pull through a loop, yarn over, pull through both loops on the hook to make your first double crochet.
3. Add 11 more double crochet stitches to the same loop.
4. Now to change colors and close the loop. Insert your hook in the first double crochet that you made (see step 1), and dropping the old color, grab your new color, and pull a loop though both gray loops.
5. Congrats, you have now changed colors. Chain 3. I don't use this as my first double crochet, some people do, I don't. It's a preference thing. You can all search the internet for tricks for hiding the chain or creating a double crochet without the chain 3. This is the easy way and still beautiful.
6. Make the first 1/2 of the first corner. Do this by adding 3 double crochet to the stitch you just used to switch to blue. It's your first double crochet from step 1.
7. Skip the next three dc from the previous row and in the 4th, add 3dc stitches, chain 1, and then add 3 more dc stitches. This forms your first full corner.
8. For the next corner: skip next 3 dc stitches, in 4th, add 3 dc, ch 1, 3dc.
9. Add one more corner
10. And now to finish the corner you started with. Add 3 dc to the same stitch that you started with and chain 1.
11. To close this row and head to the next, and to change colors again, insert your hook in the first dc that you made in that color - the one from step 5, drop the current color, grab the new color.
12. Yarn over and pull through both loops to close the square and change colors.
13. Ok, your square is bigger now and so there is one extra step you need to take and all future squares will be similar. Crochet the corners the same way (3dc, ch1, 3dc) with the first corner only have 3dc because you'll finish it when you make it all around the square. Then after the corner, skip 3 DC and add 3 dc to the space in between 3dc from the previous row. See how I did that in the picture? From now on, you're using the spaces in between the 3dc stitches to guide you. It makes it way easier to keep track of.
14. When you make it all the way around, you can cut the yarn and fasten it off. You can add another row, you can change colors. Skies the limit.
Would love to see pictures of your favorite granny square, share on my facebook page!