It is very easy!
So...
open the file named "text.html". To open it you can use any text editor like "Notepad" and replace the given name and last name with yellow background by yours. You can also replace gallery name "Photo portfolio" by yours as well.
Save your file (save as) "text.html" and upload it on your server.
IMPORTANT! do not touch white spaces in the "text.html" file and do not add any extra white spaces in the file body! Just change only highlighted text you see on the picture below.