i7 5820K @ 4.25GHz | RTX 3080 Ti FTW3 | Gigabyte GA-X99-UD4 | Corsair DDR4 3000 32GB | Corsair HX 750W
SSDs: Intel 660p M.2 2TB, 3x Samsung Evo 1TB | Startech PCIe 4x USB 3.0 | Startech PCIe 2x USB C 3.1 gen2
When the setup program asked you to point towards your monitor, point to the edge of your play area that you want to be the front. In the image above, point to the middle between your two sensors, and that will make your playspace aligned properly to the grid.
It doesn't matter where your actual monitor is, the program just assumes that your monitor is the front of your space. (Hint: it doesn't have to be.)