Reha,
I used the moisturizer from the system because I bought the entire thing. Later on I found out that many people just buy the the product that they need instead of buying the whole kit (to save money). That's why i suggested you buy the clarifying serum to save you the money.
You can buy the exfoliating lotion and the night cream. They both also contain hydroquinione. You can skip the Obagi sunscreen because it makes sanwli skin look chalky. If you're satisfied with your glycolic wash cleanser...then you can choose to skip the Obagi cleanser.
If you buy the lotion and the cream, this is how your routine will go. You will wash your face with your cleanser, then apply the serum to spot/dark areas. Then you will apply the exfoliating lotion. This lotion is only used during the day time. And since its purpose is to exfoliate the skin.....you might experiene some peeling. The peeling is actually a good thing because your skin needs to shed old skin to get new fresher brighter skin. Some people peel whereas others don't. It's a system that you have to use consistently and inshAllah you'll see fading of spots and brightening of complexion.
At night, wash face with cleanser, and apply the night cream.
The products are supposed to lighten marks, even skin tone, make it more radiant and smooth, and reduce appearence of fine lines. My cousin had some dark spots around her mouth area and she used only a couple of the Obagi products a few weeks before her wedding and the result was amazing. Her skin was so luminous. I hope it will work for you as well.