Installation Of Unity Editor Is So Easy. You Can Download Directly From Its Own Website Unity-Download For Free With Less Features For More Feature You Will Purchase It.
After Downloading The Installer You Will have To Run Installer.
Click Next To Agree Their Licence Agreement
Now In This Window You Will Have To Choose What To Install
Click Next Now Give Path Where To Save Your Files
I Am Suggesting That Give Own Path.After That Your Installation Begins.
Your Download Will be finish After Some Time. After Download Run The File
Click Next And Then I Agree
Now In This Window Two Option Will Shown One Is Unity Which Is By Default Checked The Other One Is Mono Develop.
Now Choose Installation Location And Click Next.
Your Installation Begins. After Completing This Your Tool Is Ready To Use.