The foundation crochet stitches are a great alternative to starting a piece, especially helpful when you’re not sure how long to make your beginning chain. It’s perfect for clothing or a large blanket. It gives a bit of a stretch and a nice, pretty edge on the bottom of your piece. The Foundation Half Double crochet is similar to the foundation single crochet with one small addition: an extra yarn over. Let’s dive in.
Instructions:
Step 1: Begin with a slip knot, then chain two
Step 2: Yarn over and insert your hook into the first chain stitch. 
Step 3: Pull up a loop (3 loops of hook), making sure the loop is tall to keep the stitches from curving
Step 4: Yarn over and pull through one loop (3 loops on hook). This is your chain stitch.
Step 5: Yarn over and pull through all three loops. Your first Foundation Half Double Crochet is complete!
Step 6: To make your next stitch, yarn over and insert your hook into the stitch from step 4.
Step 7: Pull up a loop. (3 loops on hook), making sure the loop is tall to keep the stitches from curving
Step 8: Yarn over and pull through one loop (3 loops on hook)
Step 9: Yarn over and pull through all three loops.
Step 10: Repeat steps 6 – 9 for the required amount of stitches your pattern calls for.
You’re completed row should look similar to this.
You can now continue on to your next row in your pattern.