For actual clustering commands and examples, you would need to refer to specific devices. (What you're asking is somewhat similar to asking "give full command for switching with explanation and example".)
Clustering, as a term, implies a set of device working closely together. How tightly or loosely such devices cooperate or controlled somewhat sets the bounds of what's a cluster.
For example, something like Cisco's stacked 3860s might usually not be referred to as a cluster. This because non-master stack member function much like intelligent line cards in a chassis.
Something like Cisco's Nexus vPC might be referred to as cluster. Each Nexus runs independently but they share information to support vPC and can be configured to share the configes for "shared ports".
Something like Cisco's VSS might or might not be referred to as a cluster. With VSS, you manage the device pair as a single device, but internally the units run more independently than a 3850 stack (or so I believe).
