[Carol-3M-Stillhand]

A tie that links 2 notes is an instruction to play the first of the 2 notes for the duration of both notes put together. (without re-playing the 2nd note.)

So in 4/4 time, if you had one whole note in one measure (takes up 4 counts which is the entire measure) and that note had a tie to a half note in the next measure, followed by 2 quarter notes, you’d play that first whole note and hold it for 6 beats before playing the 2 quarter notes that follow the tie.