How to Show items from multiple categories on home screen ? All together.

[robertwebsite]

I notice by default it shows the items from the first category in the sort order as the home (main) page inventory.

I want to be able to select and blend together items from a few different categories on the home (main) page, when people first come to my site.

How do I do this in admin ?

I know the option to actually show the categories, but I want to display/sell items from multiple categories all put together with no category headers, just a bunch of items.

Some of my categories don't have enough to fill the whole home page.

v1.3.9h
Never upgraded
No addons that I am aware of, but I am using a custom template, and the developer installed it for me.

[robertwebsite]

I mean how do I get it to show products from multiple categories on the home screen ?