Multi-select problem: How does the next paragraph end?

How to make a simple home hydroponic garden
Cut out a piece of plywood measuring 1x1.5 m, and 2.5 cm thick.
This will be used as the bottom of the hydroponic bed.
Cut two pieces of lumber 15x150 cm, and 5 cm thick.

Pick from: (I). Cut a further two pieces of lumber 15x85 cm, and 5 cm thick. These will be used as the siding of the hydroponic bed. (II). The heavier each piece is the bigger the bed will be. Cut two pieces of table lumber 20 cm in diameter. (III). These will be used as the bottom of the bed. Take lengths of wood 2x50 cm. (IV). These will act as additional boards to build the outer perimeter of the hydroponic garden. Mark your perimeter on the plywood with a pencil.
(I).