LEOlabs operates its own radar systems that point upwards-ish. The "beams" you see are the fields of view of their radars. When an object crosses that field of view going at orbital speeds, LEOlabs tracks it and uses the partial trajectory information to figure out the orbit of the object. From there, it can potentially associate that object with existing objects in its own and other databases (the US Space Force, which operates its own radars, is one of the best-known).

It then sells that information to spacecraft operators, who may be using the orbital information to determine if their spacecraft has a risk of hitting another object in space, or to figure out where their spacecraft are in the first place (usually when they're not talking to the ground).