How do I make a login menu

I am wondering how to make a login menu? I know how to do it, but if you go onto a different device, you can't go on that account. How would I make it so if you make an account, it won't say the account doesn't exist on another device?

I'll give you some bread crumbs,

http://c2rexplugins.weebly.com/

Look for the Rex Authentication Plugins for Parse.

Basically how I was doing it was using the Parse service but since it's being shut down January next year I'm currently looking for another option myself.

It was super simple, Just put in a Javascript Key and a App ID key all found on Parse do a little magic work in construct 2 with events and bam done.

But I dont want to sign up for anything... Is there a way to not sign up, or download stuff that arent .exe, .jar, ect? Im not planning on a virus anytime soon...,

Rex plugins are well known and trusted by many Construct 2 developers myself included. Other wise you'll just have to figure it out.