Basically, if you send the IRS 20% of your gross business income each quarter, then come tax filing time you'll be fine. Now if you have reason to believe your total household income from all sources will exceed $200,000, then you'll want to send the IRS at least 25% of your gross business income each quarter.
"do I enter only what I made in that quarter "
Yes. But it's a whole lot easier and simpler to just pay your quarterly taxes online at http://www.irs.gov/payments and remember to "PRINT" "YOUR" "RECEIPT" when done and file it with your business paperwork.
Also, if your state taxes personal income you'll need to pay your state quarterly taxes too. You'll have to check on your state's website to see what payment options are available to you. Not all states have the ability to pay your quarterly taxes online.