If you want access to the menu bar on your Mac using the keyboard, here's how it is done.

Hit Control + F2 and you'll get the focus into the menu bar. Once you hit Control + F2, the apple logo in the left menu bar will be highlighted. You then use the left and right arrow keys to navigate to the various options in the menu bar. Once you get to the option you want, use the down arrow key to display the options in the menu. Once the menu options are displayed, you can use the up and down arrow keys to navigate between the menu options.

If you want to get out of the menu bar, press the Esc key and you'll be out.