Did you check if Employee already has such a field or table ? Please do this to avoid duplication. If you feel that table does not meet your requirements, you customize that table and you will be done.
Case 2 : Table does not exist
Then you ought to create a new custom table which is a child doctype. (Tick on Is Child)
Since a Employee can have multiple references, you need to do these things :
Create a custom child doctype
This is a table which include your fields - Name , company, phone number, email ID etc. All of these fields can be data.
Now you need to decide where you wish to position your new references table. When you find a suitable place, Click on Customize from Menu.
Find that position, create a section break if needed (I recommend this plus this adds to organization of the form), insert a new field of type Table and add your child doctype name in Options there.
After you are done, it will look like this :-
Expanding the child table field, it looks like this:
For each field that is required in the child doctype, check on In List View and they will be visible. Expand the field and that option will be available