Use the button at the top of the Account Details screen to open the Additional Social Media links.
If the button is not visible then it needs to be enabled in the User Profile setup, click here for more information.
All the links apart from Blog are just the Company Name (
). You may need to check exactly what the ID is for each one for any particular Company. Using the example of FIVECRM, the actual URLs they go to are:
Facebook: https://www.facebook.com/pages/FIVECRM
Twitter: https://www.twitter.com/FIVECRM
LinkedIn: https://www.linkedin.com/company/FIVECRM
YouTube: https://www.youtube.com/user/FIVECRM