Trilobot Servo Motors

I’m new to the robotics side of the raspberry pi and have recently put together a trilobot kit. I’ve added a camera and managed to get some AI features working.

I want to be able to control the two motors using a servo or similar? I know I can update them to MMME.

What would I need to purchase to do this? My idea is to have it follow a line using to camera and also making the ultrasonic sensors smarter.

Any ideas would be great!

Ps. I work in STEM education, I want to show off this to my students!