Use flange head screws(for examle Kreg screw) to fasten it onto floor.
Remix from here: https://cad.onshape.com/documents/4d3a739ebe0a474b984ffe8f/w/e2f4c5a6877a94a5fa421d1c/e/d85fd33e6a7faa3d45f7a8c5
The author marked this model as their own original creation.