I understand that 40 days prior to a soul being brought down to earth it is matched with another soul and their union to be and its details are announced. How, and where, does one look for his True soul mate? and how does one know he has found his TRUE soul mate?

You can’t know. You should find someone compatible whom you love and respect and who loves and respects you, make your decision and pray for Divine assistance. If your question is not just hypothetical, I wish you the benefit of that Divine assistance in establishing a "bayit ne'eman b'yisrael".