FB WORKOUTS EASY ON THE KNEES

Hello guys!! I 'd really appreciate some help considering choosing a FB workout video to workout my lower body without giving a hard time on my knees. I kind of injured (I think) me right knee a few days ago, while I was doing side lunges as part of a warm up. Those are always hard on my knees so lesson learned, no more side lunges in the future. I also fell after my bath 2 times in a week and I was mildly injured in various places on my body so most exercises hurt. Anyway, I was sedentary for about two weeks before that failed workout attempt due to too much anxiety/depressive mood, and I can already see and feel the difference in my body; it feels like I haven't worked out since a long time. Now that I 'm better emotionally I want to start again, I 've already workout out my arms and abs so today it was lower body day. I tried pilates but it doesn't do a thing for me, I 'm losing motivation due to boredom and I really need something to wake me up. Do you guys have any suggestions on specific FB lower body workout videos that are easy on the knees and at the same time somewhat challenging? Except for pilates..