Whats the best route to getting a referral for specific clinic that i need to go to?

You ask the doc who treats you, or his/her office staff. If you just need the name & have a plan that allows you to self refer you can check the plans list online. If your plan requires that your doctor decide you need a referral the doc will have their own process. If they agree you need a referral they can authorize it. Some specialists will not see self referred patients.

Through your primary care physician, who based on physical exam and history can make a referral to a specialist. Not all such requests result in a referral, if felt not necessary from a medical standpoint.