Emergency help about create host HA.

Hello.

I have two servers that I installed VMWare ESXi 6.5 on both of them. I have an EMC CX4-120C8 and I want to create host HA. I mean is that when server 1 failed then server 2 replaced automatically but I don't know how can I do it. I'm thankful if you advice me step by step.

Thank you.