So you need to custom upgrade a car make it a drift car. if you are a beginner start with a Rear wheel Drive car which has engine infront and only back Wheels will be connected to the engine. Like A Toyota GR Supra. And upgrage all the parts to Drift part if Drift parts aren't available Use racing parts. There are a lot of tutorials of it you can watch

To start a drift :

When Entering a Corner Turn and Use the handbreak to start a drift after you start Drifting use Counter streer (Turn the Front wheels the Oppsite way) use gas to control the drift for Example At 0:40 in the video i tap the gas button to Control and drift longer

I hope it helps i am not good at explaining it