Can someone describa this suffix is all about. I mean, sometimes you have to say a word who got two words in one.

Like

Strawwberry-Plant
Tree-Chair
Iron-Ring
Rail-Way

And so on, how do you know to make a great word in all theese four words?

I mean, in Mask/Fem,Neu. Are they some special rules about it?

When you describe for example time with a another substantiv you change time to adjetctic (Time=Morning/Day/Evening).