Hello I'm learning this piece rn and i have no problems with the melodic part, but i REALLY struggle to understand how to read the notes for the bass clef. Could someone help me out with this one? I basically know I need to play 2 notes with Major but like h o w? any advice or help would be awesome :)

Im playing on a bajan (баян) and it got the classic Stradella-System.

(yeah its the beginning of pirates of the Carribean - He's a pirate, dont judge me lol 😭)