http://www.hitorstand.net/
Look at the Basic Strategy and play this game at the same time. On the Basic Strategy chart, the number in white is your total and the number in yellow is the card the dealer show (he only show one single card). If you see H, you need to hit (take another card), and refer to the chart again. If you see D, you need to double, which is you double your bet and take a single card, if you see stand, you need to stand and stop taking any other card. If you have a pair and you see P, you need to split: double your bet and separate the pair into 2 different hands, you will receive a card in each and then you can play them separately.
Practice, practice, and practice even more!