How to add the Dropbox icon to my new device?

Megan .... sorry for the delay in responding. After struggling with your program for several

I have to tell you that at this point I am sorry I signed up for Dropbox and may just unsubscrbe unless I can utilize it in the simple way I imagined.

I am a year away from celebrating my 80th birthday. My computer usage and needs are very basic. On the other hand I am not a neophyte. I have used a number of macs for many years and usually accomplished what was needed without too much trouble. But my concern is that Dropbox seems to offer so many features and capabilities that my most basic need -- simple, reliable backup storage -- appears to have been forgotten.

I realize that may be an unfair comment because I have little patience for technical stuff that goes far beyond what is needed. But one look at your long list of tutorials is enough to send me looking for an alternative, SIMPLE, method of backing up my important files and photos -- without any further bells and whistles. Simple and Basic is all I need. Can you assure me in simple,  non-technical jargon what I have to do to use Dropbox in the manner I would like? For example:  Can I simply load my files into various folders, drag them to the "Upload or Drop" box on your site and be done with it?

Thank you for your patience with me.