When you see a tab is highlighted in orange, this means there is still input pending from you on this tab
When you see the option "change columns" on the screen, this means you can custom-choose which columns you wish to see on-screen and export to PDF or CSV.
Where is the save button? Everything you enter in the application will be saved automatically unless otherwise indicated. You will be able to see the audit trail on the right-hand side of the screen as per screenshot below.
You can bring up a list of all available choices, for example, when linking someone to a new group, by pressing the down arrow on your keyboard.