The module MyCompany_MyModule will add a new page in the admin interface to display a custom entity in a grid. You created a controller for this grid MyCompanyMyModuleControllerAdminhtmlCustomEntityIndex
A. Register my_module route for the AdminRouter in MyCompany/MyModule/etc/adminhtml/di.xml
B. Create a new menu item in MyCompany/MyModule/etc/adminhtml/menu.xml
C. Specify the my_module/custom_entity URL using a @route annotation in the action controller execute() method
D. Register my_module route in MyCompany/MyModule/etc/adminhtml/routes.xml