How to Foundation Single Crochet
To foundation single crochet, start by making a slipknot, then chain 2 stitches. Next, insert the hook into the first chain, yarn over, and pull it through. Loop the yarn over and pull through the first loop on your hook before looping over again and pulling through both loops. To continue the row, put the hook in the stitch you just made, loop the yarn over and pull through the stitch, yarn over and pull through 1 loop, and yarn over and pull through 2 loops. Repeat this process until you're at the end.
Make a slipknot. Before you can start your foundation single crochet row, you will need to make a slipknot. To make a slipknot, wrap your yarn around your finger twice, and then pull one loop through the other to make a loop with a knot at the end of it. Slide the slipknot onto your hook, and tug the yarn to secure it. Chain two. Next, you need to chain two stitches. To do this, loop the yarn over the hook in front of your slipknot. Then, pull the new yarn through the slipknot to make one chain. Then, yarn over and pull it through again to make the second chain. Insert hook into the first chain and yarn over. Identify the first chain you made, and then insert the hook into this chain. Then, loop the yarn over the hook and pull it through the chain. At this point, you should have two loops on your hook. Loop the yarn over and pull through. Next, loop the yarn over the hook and pull it through the first loop on the hook. This will make a chain of one and you should still have two loops on your hook. Loop the yarn over and pull through both loops. To complete the stitch, yarn over your hook again and pull the yarn through both of the loops on the hook. Now, you should only have one loop on the hook and you are ready to continue the row. Mark your first stitch with a stitch marker. Some people find it helpful to mark the first stitch in the row with a stitch marker. You may want to do this at least the first few times that you use the foundation single crochet stitch. Place the stitch marker through your first single crochet stitch. Insert your hook into the stitch you just made. To continue the row, you will be following a shorter sequence than you used to create the first row. Start by inserting your hook into the stitch you just made. If you placed a stitch marker here, then it should be easy to locate. Loop the yarn over and pull through the stitch. Next, loop the yarn over your hook and pull it through the stitch. Now, you should have two loops on your hook. Yarn over again and pull through one loop. Loop the yarn over the hook again and then pull it through the first loop on your hook to make a chain. You should still have two loops on your hook at this point. Do one more yarn over and pull through both loops. To complete the stitch, loop the yarn over the hook again and then pull it through both of the loops on your hook. This will leave you with one loop on your hook again and you will be ready to start the sequence over. Repeat the sequence to the end of the row. Continue to repeat the sequence for this stitch until you have the desired number of stitches in your row. Then, you can continue your project. Check the gauge of your yarn. You cannot get an accurate gauge of your yarn by crocheting a chain. However, using the FSC stitch is a good way to check the gauge of your yarn quickly. You can make a 4” row of FSC stitches and then count them to determine the gauge of your yarn and hook. This could be a huge time saver if you are trying to determine your gauge for a project. Crochet into the top and bottom of the row. Another great advantage of the FSC stitch is that the top and bottom rows look the same. This means that you can work into the top and bottom rows and get the same results. Therefore, the FSC stitch may be a good option if you want to work on both sides of your foundation row. Avoid having to redo your first row. It is common to miscount the links in your chain when you are crocheting a large piece, and this can be a time consuming mistake. You may end up having to start over from scratch if you don't notice the error until working on the first row of your project. By using the FSC stitch, you can count the stitches more easily as you go and you will be less likely to make a mistake with the number of stitches. Get a neater look. The FSC stitch produces a neater looking first row than you might get by making a chain and then crocheting into it. If you have noticed that your projects tend to look a little sloppy when you start them with a chain, then try switching to the FSC stitch for your next project. This may give you better results once you master the stitch. 
Make a slipknot. Chain two. Insert hook into the first chain and yarn over. Loop the yarn over and pull through. Loop the yarn over and pull through both loops. Mark your first stitch with a stitch marker. Insert your hook into the stitch you just made. Loop the yarn over and pull through the stitch. Yarn over again and pull through one loop. Do one more yarn over and pull through both loops. Repeat the sequence to the end of the row. Check the gauge of your yarn. Crochet into the top and bottom of the row. Avoid having to redo your first row. Get a neater look. 