There is a hut fee of $10/night/person. Expect to make new friends as the hut can get VERY crowded.
Park at the pullover at km 21 and start skinning off the road and through the forest (trees are marked) to the first bridge crossing. This bridge, and the next one, can be sketchy, but have a rope for balance. Use caution. Continue through the forest for a while - when the trail becomes kinda steep (~15 deg.), you'll know you're coming up to the old logging road. This will give you your first good look, when it's clear, at Joffre Peak at a perfect angle to see some great couloirs on the N-NE face.
Continue down the old road until just before the bend, then split off left (there should be a sign) and go through the forest again. Soon you'll pair up with the river and continue side by side until the creek becomes choked up (~4,700 ft.), where you'll split off right into the forest again. You'll then start traversing around the hill until you come out into the open meadow near the terminus of the Annaversiry Glacier. Continue up, still trending right, until ~5,300 ft. where you'll want to start heading slightly east until you see the lake. The hut is right on the other side waiting for you!