Add tooltips on a gragh

Hi, all
I am new here in Grafana. I have been struggled with adding tooltips on a graph. For example, I want to plot V1, and add v2, v3, v4 as tooltips. Is this possible in Grafana? I used to use Power BI, and it was so simple in PBI, but I so struggle when it comes to Grafana. Any help would be wonderful. Thanks!

Guli