In order to log in to your trading account in the MetaTrader terminal (iPhone) please follow the below steps:

For MT4 account:

In the "Find broker" line, enter the server name, the login and the password from your trading account and click "Login".

For MT5 account:

In the "Find broker" line, select 'Admiral Markets Group AS, then the corresponding server, enter the login and password from your trading account and click "Login".