Make some alterations to my template website.

I have a template website with big folio and I need a gallery on my html5 entry page. The gallery will have 6-7 photos in it and I will need to be able to change these myself in the future if possible. Also, on my portfolio home page I would like 3 separate images with links to the corresponding portfolios. at the moment there is only the option to have one large image, and I would like three separate ones.