If you wish to add or remove some menu item, then you have to navigate in the Post Affiliate Pro merchant panel to:
Configuration > Affiliate panel > Menus & Screens
As the image above shows, on the left side you see the menu. Of course, you can expand the collapsed menu items (Promotion, Reports). On the right side you see the available Custom Pages, but if you scroll down a little bit, you will see a lot more available menu items (predefined pages).
Adding a menu item is easy -- just simply click the "Add to menu" button next to the desired menu item. Afterwards, you can move the menu item to the desired position as easy as moving icons at your computer's desktop. You can nest the menu items under other menu item, or you can move the menu item to a higher position (so the nested one would be moved to the same position as its parent menu item).
Do not forget to click "SAVE" to have your changes saved.
Removing a menu item -- simply drag&drop the unwanted menu item to the Trash. Do not forget to click "SAVE" to have your changes saved.