Once the accounts are linked, the name of the linked account will appear in the tab next to yours.
This video has various screen captures, along with a voice over. Descriptions of what is shown in the video are described below:
Title: How to link accounts in minutes
"Setting up your linked account access is easy. First, you need to log into your account and go to the 'Account settings' section. (Video shows the my accounts & dealing summary page, and the location of the 'Account settings' section, which is the 7th and last option in the row of tabs, after 'Retirement')
Next, choose the 'Linked accounts' option on the left hand side. (video shows the 'Account settings' area, and cursor clicking the 'Linked accounts' option, which is 6th in the list on the left hand side links, inbetween 'Share dealing and live prices' and 'Email preferences and share alerts')
Here you're able to view all the accounts you have access to. If the linked account that you have access to is currently set to 'view-only', and you want to give yourself trade access to that account, click the 'edit' button and your options will be shown. (video displays 'edit' being selected, this then displays your options)
If you are changing from 'view only access' to trading access you'll need the person who you are linked to enter their online password and secure number, (video shows this) as they'll be confirming they're happy for you to have this level of access to their account. Once they've provided these details you'll now have trading access to their account.
Likewise, you can restrict the access that you have to a linked account by changing the access level from 'trading' to 'view-only'. To do this you'll hit the edit button. (Video shows this) To change from 'trading' access, to 'view-only' access, simply select the button and click 'save'.(Video shows this) You'll not be asked to enter the linked account security details because you're reducing the access that you have to the account. (video shows that this edit is being made)
The ability to amend the linked account access level can be amended by both parties. If you've given someone permission to link to your account and you want to amend the level of access they have, you can do this via the same 'Linked accounts' tab in 'Account settings'. At the bottom of the page you'll be able to see who has access to your account. To amend the access level hit the 'Edit' button next to the account that has access to yours.
Since you're controlling what access other people have to your account you will not be asked to re-enter your security details, even if you're giving someone else trading access to your account."
This video hopefully helps you understand the process, but it should not be taken as personal advice. Please remember that all investments can fall as well as rise in value, so you could get back less than you invest. This video is just an example, not personal advice.