Sharepoint Online Development - Visual representation of a list

Hi, The purpose of this project is to produce a visual representation from a list of activities occurring on specific dates. I would like your assistance in developing a view for Sharepoint that displays a matrix of sites down the left and dates along the top, the cells contain activity codes. Please see the spreadsheet attached called "Sharepoint view" as an example of the view I am looking to reproduce in Sharepoint. The data will come from the custom lists "Activity list, Activities, Sites_Sections" which are also given as an example in the spreadsheet. Regards, Jacob