Great advice from Andy and Adventure.
Exercise was a big part of my recovery as well. I had to forget what the 'experts' told me and get back to doing what I loved. Now I'm running and working on weighted squats.
If you had told me three months ago that I would be doing these things now, it would have blown my mind. Exercising helped me believe in myself again and believe that all these things were possible and that I wasn't fragile and that movement is good and safe.
In terms of the nuts and bolts of it, each person has to figure out what speed and scale works best for them. Some people dive in, while others scale up. Whatever way you go about it, practice outcome independence (focus on completing the activity, not the sensations) again and again, not giving up ground if it hurts a bit. For me, I challenged myself to do something new each time, so that I had more and more proof that I could do more than I thought I could.
A mantra I used when running and lifting weights again was saying with each rep, things like, 'I am safe, this is safe, this is good for me, I love exercising, I do what I want, I lift as much as want, I run as long as I want, I want this, etc.' I can't emphasize using affirmations enough. Each exercise is an opportunity to move again, to expand your functioning again, if you meet it properly.
Also there's a good video in my signature below, the Peter O'Sullivan one, several people talking about the progress they made exercising again, forgetting about form, etc, it's really good and maybe inspiration for you.
Looking forward to hearing how it goes!