design database and links

Good day.
I'm trying to write my first program.
I've tried creating database to use at our company for staff loans… I'm failing everytime. The program say my relationships is inconflict and then I miss some parts to write everything on the next try and every try it is another problem.

Can someone just please tell me all the basic table's I need and what row goes in each one and the links to the other table.
I made the table like this:
Customer (rows is name,surname, client no,…

design database and links