Any information on the solid (continuous) line is applied to the "arrow side".
Any information on the dotted line is applied to the "other side" regardless of whether the dotted line is below or above the solid line.
Fillet welds can be dimensioned by the throat or the leg. The designer has to specify which is used.
Its been a while since I've used these symbols, so it would be in your best interest to confirm what I've said is correct.
I just took a look at the website mentioned in another response. I see the English have a little twist on what I said, so the question is, who are the designers and who is your customer? I'm sure they will not be offended if you ask them for an interpretation. However, I'm equally sure they will be very upset if you weld it incorrectly and your didn't ask them for clarification.
Best regards - Al