The interface between you, the client, and your cloud/server based custom software will be your first interaction with the software. A MENU with buttons to start specific applications is a very common method.

An example is shown below. It is a screen shot of the Kosmopolitan Singles interface to the applications after an authorized person logs on.

The top line is a reminder of the next 7 events that are coming up.
Under the 'MAIN MENU' are buttons to click on to do various functions. This site has grown organically and maybe someday they will want me to organize things a bit better. All board and committee members have access to some functions based on their privileges.
Examples:
1) The president and vice-president have full privileges and can add/edit database records and the rest of the people can only view or search it.
2) Only the newsletter editor can upload the newsletter.