Things you will need to make the glasses:
A linear polarisation filter (get a spare parts one for an iphone, doesn't matter which),
A couple of plastic screen protectors for a large phone or tablet,
Some round lens glasses (I use these ),
Lastly, and the hardest bit, you'll need some flat plastic lenses for those glasses as you'll be sticking the screen protectors to them. I bought these in 42x1mm and these in 42x1.5mm and got them to fit, but I'd recommend buying +/-1mm sets for each as they are not made that precisely and they are cheap.
I can't photograph a demonstration right now, but I can give you a real quick explanation. Those plastic screen protectors can decompose linear polarised light into two lots of +/- 45degree polarised light. But the effect is dependent of the angle of the screen protector. So you get yourself a monitor with horizontally polarised light. hold the linear polarisation filter up to screen and rotate it till the filter blocks all the light from the screen. Now take your screen protector (all plastic protection films removed), and hold it between the monitor and filter. You'll notice light now coming through the filter. Rotate till the protector till the light coming through the filter is brightest - now you have the optimum angle of the protector. Stick the flat lenses you've bought to the protector, making sure to note which way up the lenses go, pop them in the glasses and you are done.
It'll all make perfect sense when you play around with the polarisation filter and the plastic screen protector.
You can apply the same methodology directly to screens themselves, if you have a large enough piece of plastic film. Screen protectors are convenient because they already stick. Prior to getting the 'rona I was going to experiment with this, but now I'm not going to risk it till I am well again. Any clear piece of plastic film that has been stretched as part of its manufacturing will work - they are essentially working as crude 'quarter wave plate'.