How to open and view files from folder in browser using Button inside GridView in ASP.Net

Good day

I need to open/view a file in gridview....I successfully uploaded the file to a directory on the server, and added a filename field in a table.

I can view the table data row by row, but now want to click on the file or SELECT in that row - and that click event must open the file for me..

I do not know how to go about this - any advice?? I have googled, but the answers are all different it seems, and very confusing. I would like to know the reasoning behind the actions, instead of just receiving some one else's code.

Thank you