Summoning entities is no joke. As others have stated, being a beginner in magick is bound to make your results go bad.
There is a reason spirits have attacked, harmed, drove some to insanity and even death. They don't operate on human morality, and plenty are predatory and parasitic beings.
If you really want to summon a demon, it's as easy as using a Ouija board without protections and allowing something to come through.
I'd recommend however, to study the Goetia. It's a well defined and well worked system that has produced results for hundreds of years, summoning demons to aid one, of course with the protections in place.
Here's the thing about magick. You cut corners, do something without consideration for the dangers, and ignore the methods of protection, it can and will go bad. There's a reason many magicians and witches go mad or die. Andrew Chumbley and Aleister Crowely are two fine examples.