Help needed! How to start DOUBLE STOPS?

Help needed! I think I’m ready for double stops. Which scale should I use as an adult ‘beginner’? Where should I start? What’s the most efficient way to practice double stop scales?

Background: I’ve learned violin for 6 to 7 years when I was a kid. Haven’t touch violin for 20 years…..currently double stop is the biggest obstacle in my recovery journey. I lost almost all my doubles stop muscle memories.

Really confused now and don’t know what to do…big sigh. Thanks in advance!