Help Upgrading vCenter 6.7 To vCenter 7

Hello Dear Community ,

i have vcenter 6.7 installed on

• Microsoft Windows Server 2008 R2 (64-bit)

i need help to upgrade to vcenter 7

i have installed already vcenter 7 it has his own appliance

• VMware Photon OS (64-bit)

i have 20 host and 115 VM running so please i need ur help guys

thanks