Can't login on Mobile/Website. Trying to setup 2FA

[CVex2150J]

Ok first of all ... Steam support is "The Place That Sends You Mad".
I post this at the end of 3 hours of searching on Internet, Steam Forums and more.

My needs are simple: Enable 2FA (mobile app) on my account.

Following this official guide I installed "Steam Mobile" IOS app. And "Once you've installed the app and signed in" ... I can't log into the app.

I'm getting an email at each login attempt:
> Dear ....
> Here is the Steam Guard code you need to login to account: #####
> This email was generated because of a login attempt from a web or mobile device located at {My Home IP} The login attempt included your correct account name and password.
> The Steam Guard code is required to complete the login .... bla bla bla

Question #1: Where do I use this stupid steam guard code? There is no input for it in the mobile app.

Also, I try to login using https://store.steampowered.com/ and I'm getting the same result!!!!! ... "Incorrect login." + an exact email -_-'

Question #2: It there a way to enable Steam Mobile 2FA with an account "Protected by Steam Guard email"?
Is this linked? Steam Mobile App - Can't login - iPhone 6

Notes:

• I didn't receive any email about (Verify login location)
  
• Using https://help.steampowered.com/en/ I achieved NOTHING. This "support" is like going in circle. Also there is no way to contact anybody
  
• I'm using the same network. Steam client on Windows and iPhone

Note To Valve support:
There is ZERO notes on how do we use your code and where this "Steam Guard Authorization dialog" is in you Knowledge Base Page
Steam Guard Mobile Authenticator
Steam Guard

[CVex2150J]

Ok! This is infuriating.
I tried to find a solution for 3 hours searching everywhere. I decide to retry to login on https://store.steampowered.com/ The website and the app are working now.
NOW I get the Steam Guard Authorization dialog on both.

If this was an API problem for F sake VALVE ... Show a message on the client side when there is a problem.

[Supafly]

On the app you enter your username and password on the first page and hit next. You'll then need to enter your Steam Guard code on this new page. If for some reason that isn't working and you have a phone number linked to your account. After you enter username and password and are on the page wanting the Steam guard code there are 2 options on the bottom. Can't remember which one but one will take you to an option to send you the Guard code via SMS.

[CVex2150J]

For 3 hours I didn't get that "Steam guard" dialog after entering my account name and password (website AND mobile app).
Now it's working fine. I did log into the app