I joined a Facebook group called Lung Matters: Covid, Bronchiectasis, MAC, NTM, Nocardia, Pseudomonas & more. There is a lot of good information shared there. There is also a great resource that I believe was produced by the woman who started that facebook group. It covers a range of topics including airway clearance techniques and I believe a lung squeeze (not sure it is called that) is included there.
https://selfmattersinstitute.wordpress.com/a-handbook-for-lung-matters/

I have to confess that, after nearly 5 years of feeling unwell (I had recurrent chest infections, nausea, weakness, sweats, etc for a year before I was diagnosed), I get kind of weary with always trying to eat right, exercise, do airway clearance twice a day, sterilize everything, be cautious around water and soil, etc, etc. Covid has made this much worse. However, the 6 months on the Big 3 and the resultant hearing loss and constant tinnitus are a good and constant reminder why I’m doing this.

Hope this helps.