There are a couple of ways you can accomplish the grounding. If you are in a part of the country where the ground is relatively damp (Not Sand), then you may be able to connect it to the Water Service coming into the home. You will need a braded copper cable (minimum 6 AWG) to connect it to the pipe, and it must be connected both before and after the water meter. Otherwise you can put a Rod into the ground outside of the foundation and put a hole in the wall to connect the cable to it and you electrical panel. Or drill a hole in your foundation and install rod underneath. Be careful if you decide to drill, you may hit a rock and end out perforating your basement. To conform to code you must have the ground rod at least 8' long and achieve less than 25 ohm resistance from the panel connection to ground. This page looks like it is a good reference (yaay google!)
https://hosta.atsc.eustis.army.mil/c...en5144/le1.htm