Victoria,
While I think that some variant of the setup suggested by Christina is a good oneOne or more of the ground magnetometers can be run with or without the rest of the kit.
The original setup was meant to run using a Raspberry Pi 3 or Pi 4, but has also been tested with other small single board computers that may be easier for you to buy. That software is still available.
The full Beelink type setup may be somewhat hardware specific as regards the radio component. It is pretty highly tuned to produce maximum performance with the RX-888.
On the other hand, The newer software is designed to run using a small adapter board with most mini-pc's or even an old laptop.
As the original designer (with lots of help) of the magnetometer setup and code, I would be happy to work with you.
There are a number of considerations to explore, and I would be happy to do what I can for you.
Dave Witten, KD0EAG