Ubuntu freezing and barely responding

Since I have installed this system I have had nothing but problems, it's freezing constantly, going extremely slow and becoming unresponsive via the internet browser, and accrued other app basically. I am new to using this OS so I don't know how to really do commands either so it makes it even more confusing and very very irritating, considering that I don't even know how to become my own root user makes it even more complicated and I don't know how to install applications whatsoever basically other than the ones that are offered on the App Store that you provide so if there is any help that I could get please make it really really easy and user friendly so that I can do it step by step so I can get it fixed because if I miss a step or a letter I'm lost. can I please get help with getting this problem fixed