After only a few seconds my viewfinder turns off. Do I need to clean or send out for cleaning? If cleaning is this something I can do?

Doesn't sound like it needs cleaning for that problem.
What make/model of camera is it?

"Cleaning" has to do with the sensor and really only applies to DSLR cameras because of their interchangeable lenses. When the lens is off, dust can get in. DSLR's have an optical viewfinder so it can't shut off. What kind of camera do you have?