Leg workout routine

First of all, leg workout that I do can be challenging for someone who hasn't been exercising. My regular routine is below:

1. Warming up on treadmill for 10mins. Usually it is jogging speed. 

2. Leg extension : 4 sets of 12 reps. And 1 last set with 6 reps which is 90% of your maximum strength. 

3. Leg raise : 4 sets of 12 reps and 1 last set with 6reps (90%of your strength). 

4. Squats with smith machine : I recommend using smith machine for squats to focus on legs. 4 sets of 12 reps and 1 set of 6 reps (90% of your strength). 

5. Leg press : 4 sets of 12 reps and 1 last set with 6 reps (90% of your strength). 

After those, I usually walk on treadmill for an hour.