How to use Windows web cosole

OS: Windows 10 Objective: To setup Filezilla SFTP and Putty for the first time Reference guide: https://www.digitalocean.com/community/tutorials/how-to-create-ssh-keys-with-putty-to-connect-to-a-vps

What I have accomplished: Generated public and private keys Problems: I used windows web console and got stucked to tutorial step#3

Paste the SSH public key into your ~/.ssh/authorized_keys file (see Installing and Using the Vim Text Editor on an Cloud Server):

Details: My console is showing VIM environment with black screen and ~ at the left side. I could not paste the public key. I could not key-in keyboard characters with SHIFT for example the colon character [ : ] or ~ ! @ # $ %

Help needed: How to quit the VIM and go back to default web console? How to edit authorized_keys to add public key?

Thanks in advance for your help.