Browse the forum, you'll find lots of good advice although a lot can be conflicting as differant things work for differant people.
As for monitors they come with full easy to follow instructions, but basically you prick your finger, a drop of blood goes into the machine and gives you a numerical reading. This can then be used to find out what food sends your blood sugur up. You can then avoid what gives you highs. Test before food and about 2 hours after.
The GI Diet works for me along with reducing carbs a little and plenty of exercise.