Total hours from multiple site schedules to employee roster.

We have employees at multiple sites.

Currently we have a schedule that spans a week for each site that auto totals hours worked.

I would like to make a Single Doc with a sheet for each site that checks each sheet for the employees name then adds their total hours from each site to their true total.

This will help my on duty supervisors quickly identify which employees are low on hours when seeking coverage for callouts and prevent overtime.

I also will make each shift auto total the time worked based on start and end, ,total the weekly hours worked for each employee and the site etc. Pretty sure I can manage that though.

If I can get a few pointers on how to create the formula criteria for totaling the hours then I can figure it out/apply it accross the board from there. I just got lost making my first attempt and now I have no idea where to start.

I attached the spreadsheet in question.

How about adding together a SUMIF for each time sheet ?
Your issue is going to be with the validation you've got, the employee names are not unique.
Perhaps this will be of some use