Awesome! So excited for you!
You can use regular embroidery floss (dmc stuff) and usually I use a blunt needle but really, I am a firm believer in using what you feel comfortable with.
I agree, Aida cloth is the best for just starting out. Actually I still use it because I just like the way it works for me.
14 count is the usual and most typical count of aida used for patterns. I would also invest in a Qsnap frame. It is much easier on the hands and wrist and for the fabric.
When you stitch have your stitches go the same way (although I am bad at always doing this) Your row should look like this:
Then you will come back and it will look like this:
Does that make sense?
Some people also grid their cloth to make it easier to stitch. Some start in the middle. I don’t, my brain doesn’t work that way so I start on the left side and work over.
Honestly, I just tell people do to what feels good for them. Know a few basics and then make it work for you.