Warm up

3x 1200m @ 10k pace; 1 min. recovery
2 x 800m @ 5k pace; 2 min. recovery
2 x 400m @ faster than 5k pace; 200m recovery

(now, if you want to add to this workout, then add 1 more 800, and 1 more 400m).
That’s a decent workout of changing paces, working your way into the workout, and holding on.