If you're not on the same system or server, you have to ssh into her system. If you are on the same system or server, you can try to navigate into her directory but she will need to have given the proper folder and file permissions.
I have the proper folder and file permission. We are all connect to school system by using VPN. So I think yes, we are on same network. But what is command to connect to another account??
Yes, that means you want to navigate to the home folder of that user. That's what I meant when I said "The tilde is important" - the name for "~" is "tilde".
I don't know what you mean by "connect" in this context. I also don't know what you mean by it showing your directory and her directory at the same time - this does not make sense.