As others here have suggested, if you go with the Steam edition you'll get a pretty new UI with mouse support and official tileset pre-installed among a variety of other QoL improvements (and some regressions that are being worked out, but nothing that will affect you having a good time.)
If you don't go with the Steam edition, I'd highly recommend getting started with the as it provides a nice launcher that allows you to change some internal settings and select from a handful of tilesets
First of all, Flinch already linked it, but I'll doubly recommend having the wiki open while you play. It's an invaluable resource, and anything you don't understand will be explained in detail there.
For your first fortress, I would personally try to settle somewhere without aquifers (although light aquifers are newer and pretty manageable), or you may get frustrated trying to deal with them while learning.
When you get settled in, have some workshops, bedrooms, etc., try checking out the basics of the nobles system, particularly managers and bookkeepers, early on. Having a manager will allow you to set up automatic tasks that are refreshed on certain conditions (i.e., Build 10 more beds IF number of beds in storage is less than 2.) Learning this early on will save you a lot of time and annoyance resubmitting tasks one-by-one for jobs that you would much rather have automated.
I could ramble about DF and little tips for hours, but honestly blind is the best thing to be when starting. Just be patient, use the wiki, and have fun!
spoiler
Oh, and if you dig really, really deep, you might find some delicious candy, or even a group of funny clowns, if you're lucky.