You put a grounded ladder around the outside of the bottom of other ladders in order to climb them.
The provided reference video clip demonstrates how to build higher ladders in the game "Grounded." It specifically mentions placing the base of subsequent ladder sections around the outside of the preceding ladder section. This allows you to climb higher and access different areas within the game world. Essentially, each new ladder segment is "grounded" to the previous one, extending your reach.
