At primary level you can start with the MIRTE Lite, or the MIRTE Basic.
MIRTE Lite
Start learning about basic electronics and robot behaviour. By connecting two sensors to the motors (using the motor controller) one can build a robot that reacts to the sensors. Moving away from or towards the light, or not bumping into obstacles.
MIRTE Basic
Learn about software (block-based and Python). By adding a microcontroller one can create more complex behaviours and use more sensors.