Honestly, just put in one long day. Throw 8 hours at it and by the end you should be having fun. Honestly. it only takes an hour or two to get going and learn the basics. The complex things are around specific functions, like military management, or the complexity comes from a task being difficult, like irrigation. Honestly, I fell in love with the game on the first day, and it took me a week or two to really learn the ins and outs so that I could begin doing complicated stuff. Again, a lot of the difficulty isn't from the UI, it's from the fact that finding out how to manage things is tough, and the fact that some of the things you're expected to do are extremely difficult to pull off, even if the UI were great. Perfect example is dealing with an acquifier: you have to dig a large, 3d plug into the ground: like a vertical box. You dig it out, but leave it connected by a small piece of land, then you dig out underneath it completely for a few Z-levels, then you dig out the last piece holding it up, and it drops into the Acquifier, making a sort of horozontal bridge layer through which you dig a staircase to the area under the acquifier.
Or, like me, you just turn off acquifiers in the Lazy Newb Packs launch options. Newbs should probably also turn off invasions.
Finally, a quick hint to help your fort flourish: ALWAYS kill the elf traders. You get all their stuff, and they never invade or get angry. They tend to come back again, actually, bringing you more cloth and food for free!