That could take pages and pages of posts!!!
If I were you, I would go to Google and search those areas, one at a time, such as “gradnparent grandchildren activities”. I woudl then read what has been written by other grandparents. I would perform the same searches at Amazon, just to be sure there was a good book or two. This is an area that is developing as we speak, the retread parent thing. Almost every month, there is a new book about it, and everybody has a theory at this point.
WARNING: Some of the sites when you search “grandparents raising grandchildren” will be written by grandpparents who have been badly burned by the court system/ their own kids/ themselves through arrogance. Pray to the Holy Spirit and Ss. Anne and Joachim when you go to those, for discernment.