Table relationship for two tables

Hi,

I have created custom application in studio as per client requirement, i created table A(budget) with form. There is one more table and form linked with same form which is related items.

Both are having different fields, how to create relationship between both.

The user should be able to enter details of table B related items in table A form.

I want this to show relationship table below with new button, as there is no same fields in both how to create relationship. Is there any way