This is how the of the paino part would be played on guitar
(First verse)
(Do Part that?s separated 6x before Pre-chorus)
E------------------    -----------------------------------------------
B------------------    -----------------------------------------------
G---------------17-    -----------------------------------------------
D------17---17-----    17-17-17-17-15-15-15-15-13-13-13-13-14-14-14-14
A----17--15--------    17-17-17-17-15-15-15-15-13-13-13-13-14-14-14-14
E--15--------------    15-15-15-15-13-13-13-13-11-11-11-11-12-12-12-12

(Pre-Chorus) 
E
B
G
D--------------17-17-17-17-15-15-15-15-13-13-13-13-14-14-14-14
A-5-5-5---7_6--17-17-17-17-15-15-15-15-13-13-13-13-14-14-14-14
E-3-3-3--5-----15-15-15-15-13-13-13-13-11-11-11-11-12-12-12-12
(Chorus)
E----------------------------------------------------------------
B----------------------------------------------------------------
G----------------------------------------------------------------
D-17-17-17-17-15-15-15-15-13-13-13-13-14-14-14-14
A-17-17-17-17-15-15-15-15-13-13-13-13-14-14-14-14
E-15-15-15-15-13-13-13-13-11-11-11-11-12-12-12-12

(After Chorus do the same as the first verse till the end of the song)


There are a lot of other fancey things done in this but that?s the main melody.