I didnt make a photo by photo tutorial of this pants, but its self explanatory. as you can see in this picture, the sleeves of a wool sweater turn into the legs and the bottom part of the sweater turnst into the tip part of the pants. to measure the top part of the pants I used some underwear to cut the sweater to my size. then I sew it all toghether. the picture above is showing up the just finished pants, I used a cashmere wool sweater that I found in a thrift store for about 3 US Dollars once. Funny thing is that some cashmere wool underpants cost around 100 USD. The pants picture above dont look so nice when just finished, but after washing it a bit the seams dissapear as the whool blends together and with use they start looking more like pants you could use on their own. You can opt to add some elastic band around the waist like i did or some buttons, etc. picture below shows how small it compresses once it goes inside the backpack. Its pretty lightweight and when you wear them under some good pants gives you very comfortable warmth that should be enough for really, really cold temperatures (tested).