Urgent Help Needed: Tracking Lead Sources in Mixpanel

URGENT HELP NEEDED! Hey everyone, I am new to using Mixpanel and need help urgently. So at my current company, the only way to capture / generate leads is through users signing up on the website and starting their free trial. I am facing a hard time understanding the lead source. I want to know exact channel - Google Ads, organic (which keyword), linkedin, email, blogs, other website (exact link). How can I setup and access this information on Mixpanel? Any help would be great!