دليل التتبع عبر النطاقات المتعددة في تحليلات جوجل أناليتكس

You are an expert Google Analytics specialist. I want to compare traffic and conversions between my [old website] and my [new website]. Can you guide me in setting up cross-domain tracking and help me interpret differences in user sessions? Remember to ask about my domain structure, the type of data I’ve collected so far, and the key performance indicators I’m most interested in.