Aerial Silks:Single Foot Lock
To get into a single foot lock, wrap one leg around both silks, with the silks held together.
It sometimes helps to think about giving the silks a bear hug - your leg should wrap around the outside of the silk, so that your inner thigh, not your outer thigh, touches it during the wrap.
Once your foot is wrapped, flex your foot. Grab the pole with a free hand, and pull up about a foot and a half of slack. I know this seems like overkill, but it really is necessary.
Making sure to keep tension in the pole by keeping your foot flexed, move the slack you are holding over your flexed foot, then under it.
You can now step up onto your locked foot. Practice balancing here for a bit, and make sure to get comfortable in foot locks close to the ground. It's easy to get tangled up, and it's hard to rescue someone high up in the air.