Create ling graph with labels/tabs on certain points

Hello,
I was trying to make a line graph with labels/tabs on certain points but wasnt having much success. Basically I have 3 columns, the first one is date which would be the X axis, second one is magnitude which would be the Y axis while the third column would contain the labels. The thing is that the first 2 columns have around 600+ entries and the 3rd column with the labels has around 5 or 6. I was wondering how I could make this work? Any help would be really appreciated. Thanks!

*bump* anyone