This pattern is constructed from the toe to the heel.
No gauge is given since your needle size, and yarn choice will determine the size you get.

Different sizes for a custom fit are easily achieved by working more/less rows in the body/sides of your slipper.

For example:
Womens 6-7, H hook
Womens 8-9, I hook
Womens 10-11, J hook

For the size 10-11 I used a bulkier yarn, or a thick and thin ran together.