When you create/edit your Juggle profile you'll be asked to supply your LinkedIn profile to help validate your account.
Log in to your LinkedIn account and click your name or profile picture in the top left of the screen OR click Me > My profile in the navigation bar.
Copy the URL of your profile and paste in in the relevant field.
You can also upload a PDF of your LinkedIn profile instead of a CV. From your LinkedIn profile, click the More icon in the top section of your profile and select Save to PDF to download your profile.