Note that now each "silo" has an "entry" exam at the VCP level. If you get the VCP5-DCV certification first there is a 90-minute/85 question exam for cloud (VCP-IaaS) or EUC/Desktop/WorkForce Mobility (VMware View Exam).
If you don't have your VCP5-DCV exam you can just take either the VCP-Desktop exam or the VCP-Cloud exam (plus attend one of the classes required for the exam you select) to be certified.
Once you have one VCP-level certification you don't need to take another class. However, when the cert is updated to the next level there is normally a grace period (I think 6 months) after which you need to take a 2-day "What's New" class before you can take the updated exam to upgrade your cert.
Note also the exams are $225 in the US.