My website opens with this where as I have selected Our Products as “active” class.
but website shows all photos.
When I click on Our Products we get 
What is the way keep only clicked list visible. I am totally new to this. Please help.
What is wrong in that.
if you click on our products it should show all available products.
if you click on microgreens that images should be showed and so on.
When I open the website it shows all the pictures of all categories. I want it restricted to our products
Firstly, welcome to the forums.
While we are primarily here to help people with their Free Code Camp progress, we are open to people on other paths, too. Some of what you are asking is pretty trivial in the Free Code Camp context, so you might find that if you’re not getting the instruction and material you need in your current studies, the FCC curriculum will really help you get started. At a modest guess I’d say investing a 4-5 hours working through the curriculum here will really pay off. You can find the curriculum at https://www.freecodecamp.org/learn.
With your current questions, we don’t have enough context to know what you already know or don’t know, so it is impossible to guide you without just telling you the answer (which we won’t do).
It is pretty typical on here for people to share a codepen / repl.it / jsfiddle example of what they have tried so that anyone helping has more of an idea of what help is actually helpful.
Please provide some example of what you’ve tried and I’m sure you’ll get more help.
Happy coding 
please help, i have clarified my problem in following comment. Will be really thankful