I really don’t understand what you are asking. With the Stream Tracer With Custom Source, just set the volume with the vector field as the Input and some other data set as the Seed Source. The filter will trace streamlines from every point in the Seed Source.
I am guessing that you are asking how to place seed points. The only trick is to create a data set with points where you want to trace from for the Seed Source. You can use one of the sources provided by ParaView (such as Sphere, Plane, or Box) or a filter to modify an existing data set (such as Slice, an extract, or maybe Transform).
If the points in your Seed Source are too close, maybe you can try to first Transform them to scale the size up (scale greater than 1).