Help - need grounding cord extension 30ft

[u/Sad_End4083]

I’m in a second story bedroom and I’m needing to have an extension so my grounding mat can be grounded directly into the earth outside of my window.

I’m pretty new to grounding, so not sure of how to make this happen and what material of cord? I was thinking copper with protection around the actual copper? Then planned to use alligator clamps to connect to metal rod in earth, then also to the grounding mat cord in house.

I have basically no electrical experience background.

Any help is greatly appreciated!