If you have menus that are not always available, you will need to activate them on the dashboard when they are needed. Here is how to set the menu so it is visible in 2 steps:

1) Head to the Menus page of the dashboard.

2) Select the menu that you wish to manage by selecting the edit button

3) Toggle the selected menu on. The toggle next to the name should be green.

The menu will now appear on the landing page.

Note: these changes are live, so menu visibility will change immediately.