So I have this sheet music by Coldplay, the title of the song is called Clocks and I am trying to understand the notes. My question is how do I know when a flat or sharp is supposed to be played? I wrote down the notes and what I have is D A G D A G D A for the first set. However, when I watch tutorials on how it is played they use D# A# and G. How am I supposed to know that only certain notes are sharp (or flat) because when I look at the sheet and the key signature, only the F key is sharp, so how am I supposed to ascertain that the only certain keys are supposed to be sharp or flat or normal? To summarize, how am I supposed to know G is played normally (not flat or sharp) and D and A are supposed to be sharp.
Here is the sheet music:
Any help will be upvoted, thank you.