How to make /test/ and /test/test both HTML pages

Lets say I have a website called test.com. Let's say on this site I want test.com/test1 to show a blue page, and test.com/test1/test to show a red page. How do I do this?

Right now I have a directory (test1) and a page (test), however when I go to test.com/test1 it gives me this error: Forbidden

You don't have permission to access /test/.html on this server.

I've tried placing an index.html inside the folder however that doesn't seem to change anything. I am guessing I need to add something to my .htaccess file?

Sorry for asking a question which has probably been answered over 1,000,000 times, but I can't find the right answer.

Thanks :)