From your online portal go to Social Trading tab and click my account.
Log in using your trading account. To find a provider go to ratings and click New Subscription.
Alternatively, you can go to social trading and then click on ratings where you can first select your provider. Click invest and then select your trading account and click register.
Once you have successfully registered you need to press on activate in order for you to open trades once your provider does so for new positions.
