Welcome to Discuss Cooking! I think the best thing you can do now is look around - especially under the Techniques forum. Do a search on mise en place here and in my opinion, it is one of the most useful tips to cooking there is.
Basically you pick out a recipe - measure everything and place in individual bowls (or grouped together if they are added at the same time during the cooking process). If your recipe calls for 1 large white onion chopped you do that before you ever start cooking. Line your ingredients up in order of their use from left to right. That way when you start cooking you know:
#1 - you have everything ready to go and nothing overcooks while you chop something else up or measure something.
#2 - you know for a FACT you have all the ingredients on hand.
#3 - in the end this saves a lot of time and heartache!
Just take a look around and if any specific questions come up just ask. There is the General Cooking Question forum for a lot of questions and then if it's a specific question that pertains to say, beef, it can go in the beef forum
The same goes for chicken, breads, desserts, etc.