It is simple to get started and play Solarpunk 2050.

Beginner - Free

Find about 5 silly/creative/friendly/awesome people, some sweets, 4 6-sided dice (Fate dice are better). Pen and paper and get ready. Your free starter set is:
The quickstarter containing characters, the essential world description and your first adventure that starts with a rule tutorial:
Free Quickstarter Solarpunk 2050

You will also need the SDR cheat sheet for Fate:
This cheat sheet is a good staring point
This will get you at about 4 hours of fun.

Your large Solarpunk 2050 campaign

Starts with the fhe full setting book with a tutorial style campaign guiding you and your players into the hopeful world of Solarpunk 2050. The campaign is set in the interesting area of Southern Germany with lots of diverse locations inspiring even more adventures than the ones contained in this book.
Sourcebook: Solarpunk 2050

It is also time to get the full FATE condensed rules with more ideas how FATE rules can add dynamics and spice into your game.
You can get the full FATE condensed book here as well