The cluster part of a clustered SQL installation is determined by the Windows cluster group. So if a node crashes, you can evict the node in Windows. No additional work needs to be done for SQL Server to not use the node anymore.

When a newly build node is added to the cluster you need to install SQL on the new node by running the SQL "setup.exe" and choose "add a node...". In addition you need to install all service packs and hotfixes (if you haven't used a slipstream installation).