There are tons of workout suggestions out there.
IMO (and I am no expert BTW), beginners should start of in a gentle pace and low Stroke Per Min (SPM). You arent looking for fast times here, you are looking to concentrate on your form, even if that means slow steady SPM with you consciously checking your form as you go. Once, you have that down, you just choose what you prefer.
Some people prefer long distance rows of 8k and up at a slower pace
Some people prefer short sprints at a higher intensity.
Some people mix it up and alternate days with long slow rows on some and shorter fast or HIIT workouts (say 6 x 500m rows at a quick but comfortable pace with 2 min break between each interval)