Day 8
Back Up
Get your dog used to backing up by setting up a narrow path using gates, exercise pens, etc and place a treat at the closed end. Have them walk in and they will have to naturally walk back to get out unless you made the path too large that they can turn around. This is also a great way that they are actually backing up with their back legs instead of their front legs compared to when you walk towards them.
Once they're comfortable with this try without the gates and place your dog in a stand and walk towards them, the moment they start walking back, reward. Decide on what cue you want to use, reverse, back up, or back, etc. and repeat while building distance.
Lots of times dogs will sit when you walk towards them as this is an unnatural movement for them, so it takes practice and treat placement is key. Keep the treat below their chin to help prevent them from sitting.
Also go slow with this movement as they're learning and so they don't arch their back.
You can also train your dog to back up to a target! This is another great option that is a little more advanced, but it really builds a strong foundation. It's easy to go diagonally without a target, so this helps stay in a straight line, it really makes them think about foot placement like stepping back with their back feet first and they're less likely to arch their back. It also helps build up on backing up over the rainbow ladder and handstand in level 4.
The best target to learn this is a wedge/ramp or a low target like a folded up towel.