Working with VPC Security Group

Create two EC2 instance in Public 1A subnet & Private 1A subnet, make sure you select you select respective security for it
1. Public 1A subnet with Public Security Group
2. Private 1A with Private Security Group
Make sure you name your EC2 instance proper to avoid any confusion
Allow port 22 on Public Security Group for your IP, here a snippet of rule
Login to Public Instance using Public IP
Now lets try to ping Private Instance from Public Instance
But before you could ping you need to allow appropriate rule in Private Security Group
Here various way by which you add rule, you can use either way
1. Allowing entire public subnet
2. Allowing private IP of Public Instance
3. Allowing entire Public Security Group (type sg in box auto-complete will should SG)
Now, ping will go through