I don’t think a formal set of instructions exist for that. A few of us have jimmy-rigged a setup to allow for a remote top-up and I think someone did one for drain/fill.
For remote top-ups I placed a 1 gal jug inside the grobo, sitting on the reservoir lid. At this stage my plant was in mid/late flower so there was plenty of room at the bottom of the unit. I just placed the hose tubing inside the jug and when the time came I initiated the remote fill via the app. It worked well.
I think one guy on here split the lines from the drain/fill tubes and had each one running to a 5gal bucket. One for drain and the other for fill. That kind of setup would allow for the fully remote drain/fill. I’m not sure if anyone has hooked up directly to a water line or drain though.