Let's say you want a note to be sustained over 2 bars. Now, you can't just go ahead and put the same note twice in 2 different bars, because then what you're doing is simply suggesting that the note be played twice.
To solve this problem, music theory introduces something called ties. Composers use this when they want a note to exceed the conventional measures of beat and need it to be sustained over a couple of bars. It is a fairly simple concept.
Now, this is what a tie looks like, essentially, what we're doing here is extending that one A note over two bars, i.e.
4 crotchet beats + 4 crotchet beats
= 8 crotchet beats
Remember that ties are only used when it is not possible to use a standard note, for example
Over here, can you guess which notation is actually correct.
It is the first one, because tying two crotchet notes is the same thing as a minim note, so it's pretty unnecessary.
If a note with any accidental ( say, sharp or flat) is tied, then that accidental applies to all the notes that are tied together.
Like, in this case, the note being tied is C#. You can notice that the second note doesn't have an accidental near it, but it still is the C# note, because you can only tie notes with the same pitch.
Remember that there is no need to tie rests together; the silence simply continues.
For example, over here, the silence just lasts for 4 + 2 = 6 crotchet beats.
Just one last thing to say is that you always put ties near the noteheads, never near the stem; they go from head to head. And boom, now you know how to make ties, congrats!
PEACE ! 🎼 👈 that’s a treble clef btw :)