The standard tuning for each string of the guitar, starting with the thinnest string (otherwise known as the first string) is E B G D A E.
Guitars are normally tuned from the thickest string (otherwise known as the 6th string) to the thinnest string.
The easiest method to tune your guitar is to just use an electronic guitar tuner available for purchase from any guitar shop OR to use a free app like Guitar Tuna (available on both android and apple devices).
To do this, you need a reference note. This can be from any instrument that can play a clear E note.
Once you have tuned the 6th string to E, press the 5th fret on the 6th string to get the note for the 5th string.
Once you’ve finished tuning your guitar, play a chord to check that it has been tuned properly. If it sounds weird, check the strings again by following the above procedure or use the guitar tuning reference videos for each string below.
Play each video and try to tune each string on your guitar, attempting to match the sound of the specific string in each video.