Content section has a border on one blog but not on the other

I have two WP blogs:

https://www.cucinadivas.com This is the older version of WP installed via Fantastico.

https://www.zazlamarr.com/blog
This is the newer version installed by hand, so to speak. ;+)

ISSUE #1: Somehow, although I’m still using the same basic template on both of them, with essentially the same wp-layout.css, the older one is full page, while the newer one is within a frame/border.
I hadn’t noticed this until I was trying to get my sidebar to stop overlapping the header, then I saw that I had to get it within the frame on the zaz one. I’m pretty sure that it’s only going to be within the frame as long as someone has the same size display as I have, but I can’t figure out where I should look to get rid of that border/frame.
I compared the two wp-layout.css files, and the only difference seems to be those that I put in to get the sidebar in the right place. BTW, my sidebar seems to be called “menu” in the css file.

ISSUE #2:
In the older version, there is a Templates tab in the admin section. I can’t find that in the newer version. There is Presentation, but all it has is that themes have been enabled. I have no clue where to find the right file. I added a button to my sidebar in the older version for people who have Kinja to click, as well as a “topic” for memberships. I’d like to put the same things in the newer on but can’t find where to do it.

Any help greatly appreciated. Keep in mind that I’m php challenged, to put it mildly.
Thanks! Z