Photoria – completely stuck

Hi
I have installed Photoria https://www.jomotteram.co.uk/ but cannot for the life of me get it to look anything like the demo. https://demo.wpzoom.com/?theme=photoria
Pretty much all I have managed to do it set up 2 navigations and implemented them, created a page for each menu item but here are the issues I have……..

1) I created a page and called it ‘home’ so that it would appear in my navigation, but this is not the same as the actual home/ landing page of the site so goes to the wrong page when clicked – how do i get my home navigation to actually go to the home page?

2) The theme has a big slider on the home page, however there is no images in this and I am not sure how to get images into it….cannot find anything in the dash board

3) Under the home page slider I want 3 images with a header and a bit of text under it – i don’t want these to be latest posts, I want these to be constant.
I would have thought I would just create 3 posts however there doesn’t seem to be anyway of getting those posts onto the home page.

4) I want a potfolio / gallery effect on some of my pages. I have used the gallery option but there doesn’t seem anyway of changing the style /size of these gallery items or putting a description with them. Not sure the gallery is the best thing to use here?
This is my page https://www.jomotteram.co.uk/?page_id=22 but i want it to look like this but with a side bar which my page already has
https://demo.wpzoom.com/?theme=photoria

5) In general, how do I get posts to sit on a particular page? Or should I not be using posts? I can seem to put them in catagories and but cannot see to assign that catagory to a specific page?

I’ve looked at the reading material related to things like posts but it tells you all about how to create such things but not how to link it all together…could do with a step by step guide really.

Not sure if its me or whether this is just a poor theme

Grateful for any advice at all.