Guitar tuning is so simple, even a monkey can do it.
Eventually, you will learn to hear the tones of the strings, and tuning your guitar will become second nature. The only way to do this is to gain experience. Until then, you may want to invest in a tuner, which is very affordable. This doesn't mean you can't tune your guitar right away. It will just take a little more time as a beginner.
If you haven't gone through the fretboard and string lessons, this is a good time to do so. You will need to understand the frets and know which string is which.
Using a tuner can make your life a lot easier. If you are interested in finding one as well as other effects, check out the Rhythm Guitar Store.
There are a lot of devices out there, but the best way is to learn to tune by ear. You never know when you will need to tune your guitar without help. Once you learn how to tune a guitar, it gets easier every time you do it.
Here you will learn the process of a single guitar. Because we all can't tune a guitar as well as we would like, you may want to learn a backup plan for tuning two guitars to play together.