Method1: https://<vcsaip>:5480 and select update
If you want to, download patch iso from VMware patch site and mount it to vCSA VM

Method2: command line
Full Patch for VMware vCenter Server Appliance 6.5 Update 1 (2149879)
- open VMware Remote Console
- log in
- if you get [ ~ ]# prompt type appliancesh and enter your login details
- just software-packages install --iso --acceptEulas
- shutdown reboot -r patching

 

- To stage ISO: 

software-packages stage --iso
- To see the staged content: 

software-packages list --staged

- To install the staged rpms:
software-packages install --staged

Set / Configure IP Address
- open console to vCenter appliance
- login with default username/password
- type "/opt/vmware/share/vami/vami_config_net"
- configure IP settings

More info: How to Set Up vCenter 5.1 Server Appliance (works on 5.5 too)