How to refer to entire a column in SUMIFs and VBA

[fa2020]

Hi, everyone
I have a code for summarizing personnel work time while it's sensitive to 8 hours shift, means if the user types work time for a personnel in a specific date which their cumulative work time exceeds 8 hours, this code ignores it and just write 8 hours for that personnel in that date. This code was wrote by one of this forum's users, but I want to develop it to my real world problem in excel. In my own real world problem, I have large number of rows, maybe more than 10000 rows. In the last command, you see there is SumIfs object which refers to limited rows (rows 2 to 16). I want to develop it to entire rows in those determined columns. So, there is no need to make any change in the code every time I want to run the code (I update my excel table every week). I don't know how to make such a change in my code. I need to change all references such as R16C2 to the entire column so for large datasets, I don't need to make any change in my code). I'm new to VBA. Please help me to learn.
And if it's possible, Please add some explanation between lines (green texts) so I can study the entire code.