A satellite isn’t easy to build per se, but it is surely a lot easier when done according to the CubeSat standard.
The CubeSat standard was created by California Polytechnic State University, San Luis Obispo and Stanford University’s Space Systems Development Lab in 1999 to facilitate access to space for university students. Since then the standard has been adopted by hundreds of organizations worldwide. CubeSat developers include not only universities and educational institutions, but also private firms and government organizations.
The CubeSat standard facilitates frequent and affordable access to space with launch opportunities available on most launch vehicles.
Conveniently, NASA’s CubeSat Launch Initiative has released a handy guide, CubeSat 101: Basic Concepts and Processes For First-Time CubeSat Developers
Take a look through the guide and do your own research, and if you generate some promising ideas, contact firstname.lastname@example.org so we can help you get it off the ground!