A few things to note:
To size this pattern to your own foot, you may need to stretch the proportions somewhat. Your foot should fit within the outline, and the width of the gray arrow should be less than the total circumference of your foot at that point – the portion with the slits will need room to expand and may nearly double in width once stretched out.
I recommend trying it out using a cut-up paper grocery bag covered in duct tape to adapt the pattern and make it fit you. You can then save that mock-up as a template for future shoes, adjusting it as needed once you’ve worn your first pair for a while.
The seams at the heel are color-coded to indicate what gets sewn to what. You can whip-stitch these together – the originals look to me like they were whipstitched at the base of the heel with a butt stitch on the vertical seam. When cutting the pattern, I like to leave a little extra material along the parts marked in green and trim it to final size right before sewing up so that I can fold it into place and double-check.
Once sewn, soak the instep leather thoroughly so that it’s stretchy and expand the netting portion. I like to start the lacing as shown on the diagram by threading the lace through point A from inside to outside, then running through B, C, and D (also from outside to inside. Pull this snug to start to form the tip of the toe box, then continue back and forth using whichever slits along the netting side seem to align with the holes you punch on the opposite sides. This is a highly individual choice, so experiment with what works best on your feet and use the stretchiness of the wet leather to your advantage. When you’re satisfied, set the shoes aside to dry fully and then feed them oil and/or tallow until they are soft and comfortable. Then go party like the Roman Empire isn’t dead yet.
farolfvs me fecit 