Most patients have a fair amount of pain, swelling, and stiffness the first eight weeks. They aren't always able to advance their rehab program. The first two weeks are usually focused on warm-ups, specific exercises to strengthen the muscles, followed by a cool-down exercise period.
From two to six weeks more time is spent on functional skills like walking and stair climbing. Exercises get harder and last longer starting at five minutes and moving up to 20 minutes. By the end of six weeks the knee joint is ready to handle more demanding activity and exercise.
You'll want to check with your doctor about how far and how fast you can go now. Having a physical therapist to supervise your home program is often a good idea.