I 3d printed a simple adapter to slip over the scope eyepiece with a square box to fit the camera.

The camera is just a push fit

You will also need an OTG cable to convert the camera USB plug to the mini plug on the tablet

To mount the tablet I attached a small swivel head and fitted a magnet

I stuck a metal strip to the tablet holder so it sticks firmly to the magnet

To run the camera on an android tablet you will need a free app. This is the one I'm using
https://play.google.com/store/apps/deta ... .usbcamera
The scope is 15-45 x52 - I use it at it's lowest power, this shows about 1 foot square at 10m. You can then zoom in just using the tablet to just show the black centre etc.
This is fairly bargin basement stuff - you could get the whole lot new, scope, camera, tablet for less than $100.
Making the adapter for the eyepiece will need a bit of tinkering if you havn't got access to a 3d printer, look at plastic plumbing fittings etc.