This is one tough leg workout. If you are ready for this kind of workout - go for it as is or even add in weights for those workout you can such as squats, calf raises and bridges.
For those who are either new to the workout or have issues with knees do not add any weights and maybe even cut the workout by 4 and start with 25 squats, 22 lunges, 20 mountain climbers, etc.
Even those with knee issues, you can do a very minor squat that bends the knee very little but engages the glutes and quads. Make sure the knees are in alignment to not add any added strain to them.
This workout should not be done 2 days in a row. I would alternate this with walking on the other days to keep the muscles moving and help prevent stiffness.