newbie workout question

Without looking at the plan, I would say split them up unless the plan specifically states to do them together or to do a brick.  Usually doing them back to back takes longer to recover and interfers with the next days workout.    A brick is usually a work out that involves a bike ride and then immediately going for a run.   It was named after an athlete who devised the workout.  I'm sure someone else will provide more info.

Ernie

Ernie is correct.  Best to do them apart to rest-up and fuel, especially if new and building endurance.  Last month of the plan you will see some brick workouts where you would do them back-to-back...it will be noted.

Good luck!