Final answer:
The nurse should keep the collection device below the client's chest and coil the tubes to prevent kinking, while avoiding tube clamping during ambulation and not laying the client flat to reduce leak risks.
Step-by-step explanation:
A nurse caring for a client with a newly inserted chest drainage system with a water seal should take several important steps to ensure proper functioning of the system. Two key actions include keeping the collection device below the level of the client's chest to facilitate gravity drainage and coiling the tubes carefully to prevent kinking, which can obstruct flow and compromise the drainage process. It is not recommended to clamp the tube when the client is ambulating unless specifically instructed to do so for a procedure, and laying the client flat could increase the risk for leaks. Instead, maintaining a semi-Fowler's or Fowler's position is typically recommended to promote lung expansion and facilitate drainage.