What is my laptop SSD actually doing, and how to make the most of it?

Question

I have a Lenovo IdeaPad U310 laptop which comes with a 24GB SSD. It is running Windows 8.

I understand that the SSD is there to improve system performance, as it operates a lot faster than a conventional HDD. However, I'm confused about what the SSD is doing in this particular machine. I have not actually looked at the contents of the drive until today, and have always installed software in the default location (the main HDD).

The drive contains only 3 folders, "Application", "drivers" and "Lenovo". I guess that drivers being loaded from the SSD speeds things up a bit, but less than 3GB of the drive capacity is being used.

I used to think that the point of an SSD was to have the operating system installed on it for faster boot times, but the OS is installed on the other drive.

I've also heard that the SSD is used for caching, and that frequently used data and programs will automatically be cached on it. If so, how does this work? What software manages this cache?

Is my SSD being under-used, and what can I do to make the most of it? Would I get a performance increase if I move my frequently used programs onto it? (e.g. web browser).