How wonderful! I knit my first pair of socks in December, and was instantly hooked (now I'm working on pair #6). As a recent total beginner, here are my thoughts.
Yarn. I did my first 2 pairs on "sock" yarn (fingering), but then I did a worsted pair, and the yarn was easier to handle, plus I love how the slightly thicker socks feel on my feet. DK weight is in between, but not as many ready-made patterns out there.
DPNs. I like the set of 5. I started in 7" needles on advice from LYS, but soon found the length cumbersome. 5" length is much easier to handle, although when I get to the gusset/instep there are so many stitches that I go back to 7" needles for that section, so I don't worry about losing stitches off the ends. So now I like having both lengths (and I even like having 2 sets of the short ones, so I can have both socks in progress at the same time).
Kitchener stitch is cool. I learned it off of the video on this site! I also learned how to do a felted yarn join from a video here.
Decreases. The only ones I've used so far, for the gusset and for shaping the toe, are K2tog and SKP (also called Sl1 K1 PSSO). You need 2 kinds because one make a left-leaning stitch and one a right-leaning one. So the socks look symmetrical. Both are easy and there are probably videos.
My only other advice is when you get to "turning" the heel (just after knitting the flap), make sure you are uninterrupted, undistracted, and have a marker to keep track of the lines of instructions for each row. It is quick to get through this part of the sock, and MUCH calmer, especially the first few times, if you can focus quietly.
Let us know how it goes, and good luck!
Happy sock knitter