Hi,
Sure, no worries. Off work anyway, so giving some advice is the next best thing to working 
With PT and how often, there is only this guideline: as often as is necessary to solve your problem and as often as you can fit into your day. The more often the better. Best would be twice a day initially. If you can find some exercises that you can insert into your routine that you do on a daily basis, that is worth gold for the long run, but in the initial phase, you might have to dedicate more than that and find a couple of exercises that you do every day or as an alternative do different exercises every day, but every day and try to include stretching, strenghtening and balance exercises every day.
What kind of PT for chondromalacia, general guideline from my guidebook says
exercises to strengthen the muscles around your knees
Since most people who get this are runners, most recommendations revolve around running. Amongst those would be anything that stabilizes the knee. Hence the recommendation to strengthen the muscles around your knees. This means strength training for your legs long term and coordination training short term: try something like standing on an unstable surface with one leg at a time and a slightly bent knee for a couple of minutes for each side.
e.g. on one of those hot water bags that people use to put on their stomach when they have cramps, fill it up half and half with water and air, if you have one of those around (be aware that they’re not made for that and might break and leak). otherwise something like this:
https://www.amazon.co.uk/Core-Balance-Inflatable-Stability-Training/dp/B082B9MS3N/ref=sr_1_5?dchild=1&keywords=balance+pad&qid=1618318815&sr=8-5
Problems with biomechanics often involve more than one part of the kinetic chain as a root cause, so it could be due to an instability anywhere down the chain. Stability/balance exercises are greatly undervalued imho and should be included. They activate a lot of muscles that you wouldn’t be able to target so specifically and functionally otherwise. Other than that: any strengthening exercises you find in Jonathan’s thread and that you like. His outline there is great, as said, just pick and mix from there.
As a general rule regards stretching: if it’s the tendon itself that’s affected, eccentric weight training is gold, much better than stretching, for example for stuff like achilles tendonitis. Since it’s not the tendon that’s affected with you, I’m not sure how much it will help but it is definitely worth a try, maybe your quads are shortened (although in most people they aren’t, due to a lot of sitting) and it helps. Maybe try the couch stretch that Jonathan outlines in his FAQ. Stretching alone won’t be the solution, but definitely incorporate it if you can, you’d want to stretch the quads. But don’t overdo it. Too much stretching might also just press the patella against your femur and might make things worse. As @rocourteau said, listen to your knees.
Yoga is always great, it incorporates long stretches under load and isometric strength training, which is always good and a great adjunct to any other strength training. Even more recommended since Yoga is also great for peace of mind.
Link to Jonathans post for anyone reading this who doesn’t know what we’re on about:
Let me know how you get on and as said, good luck!
Stefan