Circumnavigate in clockwise direction. At the lake, the boot trail starts at the back of the last campsite uphill from the lake. After crossing a small streamlet, it goes pretty much straight up hill, very steeply. At the junction with Pratt Lake Trail, it's marked with a small rock cairn on the uphill side of the Pratt Lake Trail. Very easy to miss.
My apologies for the sideways and upside down pictures. Even tho I oriented by phone the same way for every shot, the app saved the picture as you now see it. I can't locate anywhere on the website to edit/rotate the pictures.