external monitor

Hello all !!!

Everything Is New For Me. I'm trying to hook an external monitor (actually, I have 3). I can move the window that he is on my Mac to any of those 3 but I have only one window. I know we can divide in rows and colums I'm still looking for another window that I could divide. 

I guess you have already noticed that English is not my first language. I try my best. If you think I should use a translator, I will let me know...

Thanks for your help !

Pace