There's some erroneous information in it, e.g. saddle position recommendation is wrong. I hadn't owned a bike in ages, so my first purchase was a Giant hybrid. Nice bike, just way too heavy for that kind of ride. Aluminum frame, drop handlebars, Shimano grupo. A great bike for the money.
Different shops carry different brands.
Listen to the sales people. You'll get an education. You'll also learn how to separate the BS from the real deal. Ride lots of different bikes. Chances are they won't have bikes small enough for you, but find a shop that you like and want to do business with.