This is the six eight time signature. There are six eighth notes in one bar of ) time. The six eighth notes are divided into two groups of three.
In ) time there are two pulses within each bar, with each beat being a dotted quarter note. (This is different to * and ^ time where each beat is a quarter note). Accent (play louder) the 1 and 4 count to help establish the two pulses per bar.
The song "House of the Rising Sun" is in the key of A Minor (Am). The notes used in this song are from the A minor scale. The key signature for the key of A minor is the same as C Major, i.e., it contains no sharps or flats. It is common for songs in the key of A minor to contain a G Sharp (G#) in its melody as in bar 14 of House of the Rising Sun. For more information on minor scales see Progressive Guitar Method: Theory.
Here is an arpeggio style accompaniment for "House of the Rising Sun". Look through the chords and see which ones come from each type of minor scale. Try playing this accompaniment while a friend plays the melody on another guitar. To be a good guitarist, you need to be able to play both the chords and melody of all the songs you learn. This is the basis of rhythm and lead guitar.