How do you get rear view mirrors like this one installed?
Most of the ones listed in the link you sent are bonded onto your windshield glass. The local parts store will sell a special adhesive for this application. The mirror may even come with a bonding adhesive.
some of them clip on to existing mirror.
If you get one that requires electricity (auto-dimming, bluetooth, LEDs. LCDs, back-up camera), you will need to run wires to it if they are not present for the existing mirror.
Usually, you can remove the existing mirror from it’s mounting pad on the glass and install the accessory mirror on the same pad…Study how the mirror adapter slips over and locks onto the mounting pad. Try not to break the windshield…