Where can I enable IOS Keychain in Xamarin/vs?

Question

i am using Xamarin Forms and trying to use Xamarin. Auth to save information in the device database.. For android I did this and everything right... But when I run IOS I have this mistake...

> Xamarin.Auth.AccountStoreException: SaveAsync error = error = Could not save account to KeyChain: -34018
Add Empty Entitlements.plist 
 File /+ New file /+ iOS /+ Entitlements.plist
SecKeyChain.Add returned : -34018
1. Add Keychain Access Groups to the Entitlements file.
2. Turn on the Keychain Sharing switch in the Capabilities section in the app.

I’m using these lines in code Behind:

        account.Properties.Add("teste2", "1");
        account.Properties.Add("teste1", "usereee");
        AccountStore.Create().Save(account, "clastech_montana");

That’s all I’ve done so far... I’ve done a lot of research and I don’t think I know how to turn on the Ios chain or if I did something wrong... it seems that I have to call on my Ios Veloper Account...I applied there, but I don’t have the credentials (credentials and id - something like that) option that they say I would have. someone can help?!

There’s no place to turn the key here