More than expected

So I've been reading up on a few things, trying to decide how best to approach the idea I have.
Unity, sounded like a good place to start, but I felt quickly overwhelmed by the complexity that was offered.
I was toying with the idea of using a massive layout table for creating the game grid/map.  Also, at the same time, knowing that it probably wasn't the best approach.
What does it mean to create a map, in the context of a game.
Apparently, it means a whole lot more than I was expecting. I am reasonably comfortable building up the game code, the logic for  the elements that I want.  But putting graphics into it has always seemed so daunting.
So I got thinking about the types of games I have enjoyed, and the kind of thing that I feel would be achievable for a single coder. 
Generating a random map would, to my mind, be a great way of prolonging the game experience.  No two maps the same, replayable.  That kind of thing  - Angband, and other rougle-likes, or Gnomoria.
I am pretty terrible at drawing, so rather than bug my partner to do all my icons/sprites and what not, why not 'simply' code the whole thing.
Well in my naivety, I thought that it would be a simple process.  I was wrong on so many levels.
I stared at the screen last night simply not knowing where to start.  The sample code I had was good.  But I wanted to understand how to build it up myself without simply a copy/paste of someone elses code.
At the core of this issue is that I feel I still don't know enough of the basics to do the 'simple' thing of drawing a randomly generated map.   My confusion is still there but at a higher level.  I at least can understand that I was trying to take a running jump and not simply a step.
Going to try to take it easy tonight and pull back toward something that I can achieve more quickly. I wont be losing sight of what I want to do, but I need smaller pieces at this point in time.