It's hard to explain how it works without those equations. But I've talked to our engineers, and this is the best we came up with:

The tablet access to the Forum seems to be a wireless signal analogous to the signal we would usually use to connect to the internet (computer-based communication network where we would find mundane forums of this type), but with the signal being broadcast along a different dimension from normal space, where the apparent distance to the signal's source does not change based on location. Using some of the structure of the device, we've found a way to orient other signals in that same direction, at right angles to normal space.

We have access to another technology that allows us to move matter remotely between two points, by means of paired devices, made at the same time, which exchange signals between the pair and then instantaneously folds space to exchange the two areas. As far as we know, it isn't possible to make a new device to connect to an old pair without billions of billions of tries to get a match with a random device. But the signal for the Forum gives enough information about its source that we think we can narrow it down to only thousands of tries, which we can do very quickly.

I've noticed that descriptions of how the Many Worlds Forum works are pretty wildly varying, though, so honestly I'm not sure that this will be useful to you. I'd guess just see if you can "follow the message back" toward the forum, whatever that might mean, and take anything that does space-shortening transit that you can point in that direction. Maybe try looking for signs of magic traces wherever you found the jar of lights?

The place it was from didn't seem important, it was the sort of area you would expect to have something that would be useful to someone.

I will more closely investigate the magic my jar uses to communicate with the other worlds, and attempt to combine its method with wandering magic.

I thank you for the information and advice.