setup wr21 for simple vpn tunnel from japan to rv042 in the US

I have already put the WR21 on a verizon network, but I’m unsure how to configure the tunnel to my RV042 cisco router.

How do I create a VPN tunnel to this device with just the verizon connection. I have both devices here for setup but the WR21 will be used in Japan

Refer to the doc in the link