Examples:

A gerund phrase can act as:

• Subject : Riding a camel looks easy to me.
  ( Riding a camel  is a gerund phrase acting as a subject in the sentence.)
• Direct object : He enjoys milking the farmer's cows.
  ( Milking the farmer's cows  is a gerund phrase acting as a direct object in the sentence.)
• Indirect object : She likes baking cakes for her children.
  ( Baking cakes  is a gerund phrase acting as an indirect object in the sentence.)
• Object of preposition : He's thinking of running a seafood restaurant.
  ( Running a seafood restaurant  is a gerund phrase acting as on object of the preposition of  in the sentence.)
• Subject complement : Mike's only pastime is cycling along the coastal road.
  ( Cycling along the coastal road  is a gerund phrase acting as a subject complement in the sentence.)