How to transfer the music from my iTunes library to my iPhone?

Basically, I recently had my iPhone replaced and it was backed up with iCloud, so all of my information transferred, including the music I purchased on iTunes. The music that I did not purchase through iTunes, however, like CDs that I downloaded onto my computer, didn't transfer, but they are still in my iTunes library on my computer. I currently have 891 songs on my iPhone, but I should have 1116 if the ones from CDs were on it too. I want to replace all of the songs currently on my iPhone with my iTunes library that is on the computer rather than having to sort through all of my music and figure out which songs I need to download onto my iPhone. Is there any way I can do this which is absolutely guaranteed to work? I don't want anything to get deleted from my iTunes library. Also, since I will be connecting to iTunes on the computer, should I turn off iCloud backup?

Simply connect the iPhone to the computer select music iTunes and make sure that it is set for sync then press sync now it will not replace or delete any song.