Playing water?

I've got over 500 hours and spent years playing. I've done some Team PvP, but also play a lot of PvE with my friends. (I've not played the campaigns yet; I feel I should do that at some point!)

In that time....I can count the amount of times i've made a dock on one hand.

Yes, i'm not kidding you - i've never really played water. When I first started playing learning about the different water units and cards intimidated me (It was a culture shock enough coming from older AoE games, learning about cards and home cities and whatnot) and so my solution was - just don't do it.

I don't lame Deccan or Great Plains, but i'll just call dibs on not going water for a given game.

However, I recently watched this match by SamuraiRevolution, and it actually looks really fun - that Eco he got going looks crazy. So, i'd like to give it a go.

The problem is that I know nothing about going water, what units do what, what cards are good, anything - and most guides assume some level of basic knowledge. I don't even know what the resources on water are like, or what civs are even any good on water.

Can anyone ELI5 water play/booms to me?