Cook your pasta for as long as your box calls for. Once it's all cooked wait a few hours for it to cool.
Cut about a fourth of a block of cheese into cubes.
This step is optional but it definetly tastes great. Just add about as much as you want, it won't change the way the rest of the pasta tastes.
You don't need a specific amount of olives either. Just cut up as much as you want!
Grate about a fourth of an onion into your bowl of pasta.
Add 2 teaspoons of oregano to your pasta.
Your going to need to put about half your bottle of Italian dressing to your pasta. Make sure your box is 12-16 oz. If your box has more or less pasta just add more or less dressing.
Once you've put all your ingredients in a bowl, mix well. Let this sit overnight, if you made it in the morning try to let it sit in the fridge for at least about 5 hours.
When your ready to eat add a little more dressing to make the pasta moist. The dressing that you put in the night before has soaked in to the pasta so that's why you have to add more.
I hope you enjoyed this and let me know how this turns out for you!