This is from Kiss The Rain by Yiruma but the sign before the notes keep bugging me as its position on staff keeps changing and likewise the octave keeps changing and I can't understand how to play it.Like the notes in box are same but the one on the right is of higher octave
That symbol is a "one sixteenth musical rest".
In the notation you supplied, there is a sixteenth rest followed by three sixteenth notes. The four events all fit inside one quarter note.
The two little tails on the sixteenth rest are like shortened versions of the double beams that connect the three sixteenth notes together.
Often the typesetter will move rests vertically up or down the stave so they align better with the phrase they belong to. The vertical position on the stave doesn't affect the duration - it's to make the music easier to follow.