Find or make a Google Slide that will be your certificate template
Make sure not to include the quotation marks
Make sure the sheet only contains the names, and they are all in the first column
It can be found in the url like so: https://docs.google.com/spreadsheets/d/ID_WOULD_BE_HERE/edit
You can find the code here: https://github.com/jere-mie/Certificate-Generator
This should be in the "var ss" declaration located on line 15:
var ss = SpreadsheetApp.openById('ENTER_SHEETS_ID_HERE');
Simply hit the run icon (like a play icon) at the top to run the script, and it will automatically edit the template slide to include a unique certificate for each name in the Google Sheet
In the future, I plan on releasing this as both a standalone addon for Google Slides, as well as a web app that can be run by anyone from a convenient site.