Default want to start making a custom rom where do I start?

Hi I'm a newbie into android custom rom development. I'd like to know more about it and utilize a Notion Ink Adam as my test device. I want to port the latest version of android (maybe ubuntu or win 8 would also do) I just want to see that the Notion Ink Adam 1 works as a usable device and all peripherial devices work as well eg. Camera and the pixel Qi Screen etc. However I do not know where to start. I went through a youtube video which talks about android internals .. So far I have collected the below queries.

1) Why is it that installing android on devices is not the same as installing a regular operating system on a machine.?
2) Is my device really a paper weight if it gets hard bricked. It cannot be recovered Period ?
3) Since the Notion Ink Adam is based on a Tegra 2 process, would it be correct to assume that if a cyagenmod android os works on another device with a similar processor by some other company it will work on the Adam. Thanks.