What does it mean for the set of Co-$H$ structures of Moore space to be in $1-1$ correspondence with Ext $(G, G \otimes G)$?

Question

I am trying to understand the following abstract of a paper written by MARTIN ARKOWITZ AND MAREK GOLASINSKI :

I am building my understanding of co$-H$ structures on the book of Marty Arkowitz named "Introduction to homotopy theory" and my understanding of EXT derived functor on Harpreet Bedi homology series lectures which I think depending on the book of Weinbel who is a student of Joseph Rotman.

Could anyone help me in understanding this, please?

Also, Is that question suitable to be send on Math Stack overflow?