I am not sure how well you know Bryce so I will assume nothing and do this step by step.

Open bryce. Select the ground terrain and press the delete key.

Click the right facing arrow next to SKY AND FOG. Slide down to the last row of preset skies. On the left hand side is one called Starfield. Select it and click the tick.

Click SKY AND FOG. This opens the atmospherics options. On the right hand side is down facing arrow. Click it. Select the SKY LAB option.

In the Sky Lab click SUN AND MOON if it is not already selected. Select CELESTIAL and  STARS. Turn EVERYTHING else off and click the tick.

Hit render and you will have a basic starfield.

By playing around with the options you should get something you like.

I hope this helps.