I cannot add new automated volume points in Logic Pro tracks, when I click on the line, no points are added

Yes, you do need to double click to add a new point. Double click the point again and it gets deleted.

Probably so it doesn't add a point every time you want to move the point or create a curve. Search Logic Automation on Youtube for tutorials.

It is working properly. When you click on the line it adds a point and the line stays horizontal until you add a second point a little after. The first point is the the start of the automation and the second point is where you want your automation to end. Lets say you wanted the volume to go down from where it was. When you click on the second point you can lower it to the desired volume. You can click on the line a little later to add another point and raise the volume back up.

[Edited by Moderator]