@Flash1955
I'm sorry that you have the haematoma (Swelling filled with blood) and you can't bend your knee yet.
But be assured that this is all going to resolve, given time.
Complete recovery from a knee replacement takes a full year and your knee is only 18 days into that year. You have plenty of time. There's no need to rush.
The swelling and the hematoma are physically preventing your knee from bending and nothing you can do in the way of exercise will make it bend more.
Have you contacted your surgeon about the haematoma? If not, I think you should. Sometimes, it's possible to remove some of that blood with a syringe.
Meanwhile, reduce your exercise and spend as much time as you can resting, icing and elevating your leg, to try and reduce some of the normal swelling.
There's no need to rush to get ROM (Range of Motion) because it can continue to improve for a year, or even much longer, after a knee replacement. There isn't any deadline you have to meet:
Myth busting: the "window of opportunity" in TKR
In any case, it's not exercising that gets you your ROM - it's time. Time to recover, time for swelling and pain to settle, and time to heal. Your knee has the potential to achieve good ROM right from the start, but it's prevented from doing so by swelling and pain. As it heals and the swelling goes down, your ROM (both flexion and extension) will gradually increase, whether you do any formal exercise or just let your normal activities of daily living be your exercise.