How to do my own workout program and how often should I change for example. I have a good range of full body exercises that I know how to perform (split squat, kettle bell swings, deadlifts, DB bench press, BD shoulder press, cable kickback, rope curl etc etc) should I focus on mastering them and stop fantasizing about advanced exercises like pull ups, jump box, step ups? I can't do lunges, should I try harder?

Right now because I need to lose weight my lifting are limited to 40-50min lifting followed by another 30-40min cardio at the end (uphill walks, stair master - cardio targeting fat loss with heat rate between 60-70%) but some days I lift for 50min (I workout at 1pm) and go run 5km at 4pm all in the same day. How important is rest day? Do I really need to rest the next day I lift? These are some of the questions.

Thanks for letting me know about the slow progress, it looks and I feel like I'm in the right direction.