Please help me to understand the bold sections:
I find it helpful to describe Tin Can using layers. On the surface, Tin Can is quite interesting with many
capabilities to explore and understand. Just as you start to take it all in though, you realize there is more
goodness hiding just beneath the surface.
The second sentence simply means “Tin Can is quite interesting, and it has many capabilities to explore and understand.” “interesting with” is not a unit: you could put a comma after “interesting”.
“take in” means absorb and comprehend. “Just as you start to take it all in” means when you begin to fully absorb and comprehend it.
“more goodness hiding just beneath the surface” means that there are further good/interesting/exciting things beyond what you first see. (“goodness” is a rather unusual word here – more often used for food, for example. Probably it is used intentionally in a slightly unusual way.)