I cannot import images

Hello
I installed and activated the plugin.
I’ve watched a tutorial, but the plugin isn’t responding as expected when I enter the date (nothing happens) or try to add an image (nothing happens). I think the categories are added though, but no way of knowing.
I have been searching all over the internet for a plugin that has a filterable gallery and a lightbox. You are the only free one I found.
I’ve been struggling for a month now, trying to find something else (free plugins, templates…) but none of them seems to offer both filters and lightbox.
I don’t want to go for premium because i don’t need any other features.

I would be grateful if someone could help me here