Hello Ben, to be a solar expert you will first of all have interest in Renewable Energy. I will strongly recommend you take our free online solar training course at https://stoplearn.com/courses/power-energy/off-grid-solar-installation-training-course-free/ After this course, endeavour to enroll in the practical sessions.
At the end of the course, you would be able to do the following:

1. Know the principles of renewable energy
2. Understand the various types of Solar Panels: Polycrystalline, Amorphous & Monocrystalline Technologies.
3. Understand Load & Power Estimations & Calculations
4. Install Solar Panels for clients
5. Introducing Solar charge controllers
6. Understand and learn to install PWM and MPPT Solar charge controllers.
7. Understand Inverter & Solar Panel Specifications.