Keeping your guitar in tune is one of the most important things you’ll need to do (and redo often) as a guitarist. The most popular method of guitar tuning is standard tuning, I would estimate 95% of songs use this.
This video will let you listen to the correct pitch of each string in standard tuning. Each note will be plucked several times, so you have enough time to tune your own strings as well.
The tuning pegs you need to turn are also noted in the video, as are the scientific pitch notations, and the frequencies of each string.