How do I create a triangle with dots and space with triangular numbers?

Hey guys! I have a little homework in Java. Since it’s my first semester studying computer science in Germany I never got in touch with Java. I still need some practice and help with my homework to slowly get into Java by myself. My homework is to write code to create a triangle with dots and spaces while using triangular numbers. When I run the code, the program will ask me to type a number and when I type the number it should show me the triangle with dots and spaces. I would appreciate your help!