(This was going to be a comment rather than an "Answer", but it got long...)
I'll assume you have or can get the engineering skills, and give a few CubeSat-specific resources.
If you haven't seen it yet, NASA's CubeSat 101 has a lot of information about design, licensing, integration, and such. They don't give exhaustive detail there, but it maps out the territory so you know what to look for, and they have more specific resources, too.
You'll need a ground station to talk to your satellite. There are commercial ground station services like Leaf and Amazon Ground Station, or you can build your own and link it to the SatNOGS network. These options give you global coverage, as opposed to the more limited coverage if you build your own standalone station.
Off-the-shelf components are available, like solar cells, reaction wheels, structural parts, etc., so you can concentrate on mission-specific components. I can't evaluate the suppliers, but I have a soft spot for the name Pumpkin.
To get your cubesat up, you might get a free ride from NASA if your cubesat helps them to fulfill their own mission, as they describe in their CubeSats 101 book. United Launch Alliance has a competition to schools for free launches, that's from 2016. I don't know if there's anything more recent, but you can always contact them. Otherwise I think it's around \$250,000 to ride up in a dispenser on a Centaur. SpaceX and Rocket Lab are also in the business, Wikipedia suggests as low as \$100,000, but I haven't found specific links on short notice.
It's actually amazing how much support there is for you. It's still expensive, but space has never been cheaper or more accessible. I've never built or launched a satellite myself, I trust you'll soon know more about it than I do.