So many things you can make starting with a basic square like this! And all you need to know is the Double Crochet (DC) stitch.
DC= Double Crochet
SL ST= Slip Stitch
I used worsted weight yarn and the manufacturer's recommended hook size H8/5mm. You can use any yarn you like depending on your project.
DC in each stitch across and 5DC in each corner.
Begin with a magic circle and CH2 (does not count as DC).
RND 1: DC 12 in center of circle. Join with SL ST in top of 1st DC.
RND 2: CH 3 (counts as DC). DC 4 in same stitch. The 5DC cluster is the corner of the square. DC in the next two stitches to make the side of the square. Then repeat DC 5, DC, DC three more times to create the other three corners and sides of the square. Join with SL ST in 3rd CH of beginning CH-3.
RND 3 and up: CH 3 (counts as DC). DC in next stitches until you get to the corner. DC 5 in center stitch (3rd DC) of the corner. Repeat: DC across to next corner and 5 DC in center corner stitch, for the rest of the square. Join with SL ST in 3rd CH of beginning CH-3.
* I have a video tutorial below to break it down a little more and show you step by step what to do.
If you find a large gap between the CH-3 and first DC, try using a CH-2 instead if your CH stitches are large. I tend to CH small, so 3 works for me.
To keep your square perfect, you must make sure to have consistent tension and stitches the entire time. And also keep in mind that the larger the square gets, the stretchier it gets, so it might appear to be warped if it's stretched. Be careful how you hold your project while you are working so you are not stretching it out.