Ratchet with an allen socket in it, Drill driver if you're brave/careful... Depth bands may require a short extension?

Pull plug, screw in short 1/8" pipe nipple with a Tee and a grease zerk in it that you can get your hands on and get a bit of leverage. Longer nipple if you need the length.

Pump until grease begins to flush out around the seal.

Remove grease device, reinstall plug.

Only need to do it once a year. Do it well, seal it well with the plug.

Ken