One change affects all other pages

Hi I’m quite new to webflow so what I need help with might be quite stupid but still I would like some help. I purchased a template and I’m now using it to build a portfolio, I have a hard time understanding cms despite the video tutorials.

The problem I’m facing is that when I make a change in one page it affects every other page as well. I wanted to add an image to one of the work pages but it keeps adding one to the other ones as well. I’m guessing it has something to the with the cms and templates but I am still struggling to figure out what it is.

Here is my site Read-Only: LINK
(how to share your site Read-Only link)