This pattern is designed to fit Adult Female Size and it’s done using felt insoles which can be purchased in footwear stores, dollar stores or in Etsy shops with the little holes already punched in. If you use shoe felt insoles, you will need a sharp hole puncher or I use a leather puncher to make tiny holes and a 2mm crochet hook to attach the yarn to the soles. Pictures and a detailed explanation are in the pattern and you can research on youtube to have an idea on how this is done. PS: You can add some puff paint under the slippers if you find them too slippery. If you have any questions, please do not hesitate to contact me. Thank you for your purchase :)