Product is content like everything else in eZ Publish, so you work with it like any other "content object" of a specific "content class type" (Article / Folder / Product / Forum...).
As for your question, you want to list products horizontally on frontpage? as opposed to "?" ?
If you have ezwebin installed (as opposed to ezflow), then you should be able to click on 'Insert embed object' in the editor (Online editor) for left / center / right column, and brows your way to the folder you have products in and select Horizontally listed sub items from the 'Class' drop down.
If you use ezflow, then you can (just like in ezwebin) do this on all other content types but frontpage, as frontpage uses layout (aka flow frontpage) datatype in ezflow instead of ezxmltext as used for rich text. In ezflow you would have to use blocs to setup a automatic listing of products.
