There are lots of beginning knitting books out there. Here is
one (I haven't read it - I learned from my grandmother, too). You could explore more on Amazon, or, better yet, go to your local yarn shop and ask for help. They should be able to show you and sell you a good beginning book, and some appropriate yarn for first projects.
You want something fairly thick, but not crazy thick - maybe about 1/8" wide. Acrylics are cheap and fine for learning-to-knit projects - she can graduate to nicer yarns later. If you don't start with acrylic, get wool or an acrylic-wool blend. Cotton is not stretchy enough for a beginner who is learning to maintain even tension. Don't be tempted by fuzzy yarn or the super-slick synthetics - they feel nice in your hand, but are very difficult to learn on. It should say on the label what size needles to use. A tip is that there is no reason you cannot knit back-and-forth on a circular needle, and it is easier to travel with, so I would get that instead of straight needles.
The book you pick should show pictures of hands knitting, with close-ups that let you see which way the yarn is wrapping around the needle and how it pulls through. Bonus if it shows multiple methods (left-handed or Continental and right-handed or English). I like books that talk about how to adjust and design patterns - Elizabeth Zimmerman is a fun author for those (I recommend
Knitting without Tears), but there are others. If you find something spiral bound, that is a plus, since the book can be laid flat on a desk while you use both hands to knit.
