Hallo All,
I have a requirement to create a new excel template for the 2 new data entities. This is similar to the Purchase order header V2 and Purchase order lines V2 that exists for Standard purchase order template.
My question is how to build a template with relation between Header and lines entities in the excel just like below Standard template.

This template is a standard purchase order template where Lines is linked to Header entity.
Could some one tell me the procedure how to build a relation between 2 entities as in above template.
I have tried with my own entities but unable to form a link between 2 entites. The 2 new entities are similar to Purchase order Header V2 and Purchase order Lines V2 entities. There exists a relation in the Lines entity with Header entity.

But the problem is unlike in the standard template, in my new template I am unable to find a ++ symbol to add the linked data source.
Thanks in advance
Ramakrishna