Well there are three steps.
1. You Add a New Menu Name (what you are describing). 2. You have to add items to your menu (from Pages, Categories on the left) then click save menu. 3. You add it to one of your theme locations (usually Primary or Secondary) on top left.
After the first step when you click the + sign, add a menu name then click Save Menu is there a tab at the top with the name you gave the menu?
The check boxes next to the Pages i’ve created are unclickable. The box is there and nothing is greyed out, but clicking on the box does not check it off.
And no, there is no tab with at the top with the name of the menu
Under Theme Locations on the top left does it say how many menus your theme supports? It almost seems like javascript is turned off
There is no option for theme locations. The first thing on the left side is Custom Links