Linking leads allows you to keep track and connect leads that have a commonality. It is a great way to keep your funnel organized. For example, you can link a corporate business to all the franchise locations it has across a city.
To link a lead, click into a lead and scroll to the bottom of the custom fields. Next, determine whether the lead you are about to link is a 'parent' or 'child' in the connection. Using the example above, a corporate business would be the 'parent,' and any franchise location would be a 'child'.
Fig1. Linking a lead
Enter the first few letters of the account/company name and select from the list.
Fig2. Selecting a lead to be linked
The leads are now linked, and you can now keep track of the leads in your pipeline and how they connect by clicking on the red link will open up the detailed view of the lead. 
Fig3. Linked leads