Re: probably a silly question...building a house
Part of what boosts your credit score is actually using your credit and using it in a fashion "they" consider responsible.
In order for FICO to give you credit for credit card activity, you need to have a balance on the card to be reported; but I want to pay it in full each month( so no interest). To accomplish this, I just created a "Gas" sub-acct with my credit union and seeded it with $200 to start. Money trickles into this account when my checks are deposited to pay for the next month's gas.
Now I charge the gas during the month and my scheduled payment goes out after the balance is reported, but before I get any interest charged. I show activity on all my cards and ensure each one of them has a stellar payment history. I simply used a sharpie and wrote 1,2, & 3 on my cards so I know which order to use them in. Once I have used the card that month I just put it in my wallet backwards so I know I have used it. Anything logo facing out is still in play. If I need to fill up more I go back to cash/bank card.
Once you establish this it's second nature in a few months. It won't help you in the very short-term, but it's very good for your long-term credit and very easy IMO.