Sorry, I don't really understand this: "Then once you click on a button in the portal, all the other records will show up on the side"
Do you mean that the left side of the screen, say, will be a Form View of one customer's record, and the right side will be a portal showing all the records in the table?
If that is the case then simply define a cartesian self-join relationship from Customers to Customers (use the 'X' operator on any pair of fields) and draw the portal on that relationship.
Yes I meant 'record' instead of 'records'.
On which table/layout should I draw the portal?
Thanks for your help.
In Manage | Database | Relationships, select the "box" (Called a table occurrence) for customers, then click the duplicate button (two green plus signs). Double click the new occurrence box and change its name to AllCustomers. This is a second reference to the same table so that we can set up Sorbsbuster's cartesian self join.
Drag from Customers::anyfield to Allcustomers::anyfield to create a relationship. Then double click the line this action created to open a dialog box where you can select the cartesian join operator (x) to use in place of the default (=) operator.
This gives you:
Customers::anyfield X AllCustomers::anyfield (it doesn't matter what field you choose for "anyfield" here in this relationship.)
On your Cutomers layout, add a portal to AllCustomers to display a list of all the customer records. This script can be used for your portal button:
Go To Related Records [From Table: "AllCustomers" ; Using Layout <Current Layout>]