This is all you need
You can achieve amazing credit with what you have, but it will take a few years.
In order to build good credit you need at least two different types of credit (revolving and installment), which you already have.
Continue to pay that car loan. It will develop payment history on your report.
A paid off car loan will remain on your report for 10 years after it is paid off, and will have a positive effect.
The credit card is a revolving credit account, and is great for building credit history.
Just be carful with it. For best credit, keep usage small (a few small purchases like gas and groceries), wait for the statement and pay it in full (not just the minimum). Carrying balance on your card doesn’t build credit (too much can actually lower your score) and costs a lot of money in interest payments.
Don’t ever be late on payments. JA single late payment can ding your credit more than a whole year of timely payments can ever fix.
Good luck