"barefoot sandals" - I hate the name. These are not sandals. These are foot jewelry. You wouldn't call the equivalent to hand to gloves, would you? I hope not. It would be bracelet, perhaps ring bracelet, so toe wristlet.
This pattern is written in IN STANDARD AMERICAN TERMS for DK yarn (american thickness - Light Worsted, DK) and crochet hook Photos and instructions are included. This pattern is required chainless technique skills.