if you never baked, take it from someone who's been baking for 50 years (yeah, really, and before that i was making mudpies!) - when you start baking, start with recipes - tried and true recipes. Get them from someone here, or get them in good cookbooks with authors who test the recipes, but don't improvise. You first need to get the feel of it. Make someone's recipe, julia child's pate brisee, or her puff pastry, or some other reliable source, see how it comes out, get a feel for the proportion of the ingredients, and then you can fiddle around with it, substitute some nuts for some of the flour, or whatever.
Unless you want to wade through dozens of flat dense or dry cakes, pastry that becomes a greasy mess, etc, because you enjoy the experimentation (for me it's too frustrating) then ok. But you might want to get a professional baker's book that will give you some proportions of fat to flour to liquid, etc, and will explain the chemistry behind it all.
I can make a reasonable brisee without measuring, because i have a visual sense of how much butter and flour i usually use, without measuring. But without having made hundreds of pies and tartes and quiches, i wouldn;t be able to do it, and if it's for something important, i always measure and follow a recipe.