Amigurumi are usually worked in the round (which we will talk more about tomorrow) and therefor are usually started with a magic loop, also known as a magic ring. The magic loop is a technique where you will crochet into a loop that you can then pull tightly shut to form a round crocheted row that leaves no gap in the center.
Many people struggle with the magic loop technique, and while it's not entirely necessary, I find it to be desirable over other techniques.
TIP: I like to hold two fingers inside the loop while I'm working the single crochets. It helps me to hold the circle stable without worrying about it getting away from me. :)
I'm a right handed, continental crocheter, so this technique isn't always do-able for everyone, depending on how you crochet. Feel free to search youtube for more videos to help you. If the magic loop just isn't your thing and you choose not to do it, here is another technique for starting your ami's.
Leaving a long starting tail, ch2, sc 6 into the second ch from hook.
After this you will then skip the beginning chain and continue to crochet in the round as normal. If you happen to have a large hole in the middle of your foundation row then attach a tapestry needle to that long starting tail and go through the first 6 stitches. You should be able to pull them tightly together, going through the stitches again as needed to secure it.
Tomorrow we will be talking about crocheting in the round versus joining every round. I get a few questions about this every now and then, so I figured it was good to include! I hope you enjoy!