Using forms to create standard new posts

Hi – I’m looking for some friendly words of advice as I’m struggling to figure something out. I’m not a website designer, but dabble to help out friends and family.

I have started creating a website for my brother to allow him to show off everything he makes. He is a craftsman and no way IT friendly. I also have limited spare time so need to create a site that he can maintain easily, hence why I have gone for WordPress (again).
The sites I have done previously in WordPress are simple, fairly static pages that once created only require updating every month or so.

The new website will be a catalogue showing everything that has been designed/created by this person and is likely to contain over 100 items by the end. Items will be continually added and likewise some removed.

I have a basic design and structure to the site which has my brothers approval, but now I need a way for my brother to add all his work. I assumed the easiest way to do this was to create a submission form.

I may be trying to achieve too much, but from the point the form is completed to include title, description, sizes, narrative and multiple pictures, I want the form to display it on a description page (as a new post) and a category page.
The description will look like a basic version of a ebay or similar item page and I need to transfer the submission of the forms contents to this layout as a new item. I’d also like the new item added on the category page showing title and picture only.

Is this something I can do with something like Gravity Forms? In all the help I have read it talks about form creation but not how that content is then transferred to your template, I’m guessing that must be the hard bit.

Thank you for reading this far.