Open comments when click on photo

Hello guys.
I’m new to Gmedia and doing some pretty simple WWW for polish oldboy scouts. They gave me task to help them with their homepage made on wordpress, especially with photo gallery whitch they would share with youngers and tennagers who aspirate to become scouts as they are.

So I stucked in my job with event which would work like that: when you click on photo, and it beacome full screen the comment section automaticly shows.

Well I know it’s JS thing, and everything is possible but I’m pretty sucks in this language for know and found I need much more time to understand such complex module. If there’s possibility that some of you guys will give me hand and lead me with this dark forrest of unknown language I’ll be apriciated.
It’s really important to me to make this task completed, but I’m also aware of my weekness.
Thanks in advance folks.