"file" lookup or Record look up?
One common way to pass data from one layout to another is with variables--provided to keep the process all in one file.
Usually, you use a list view instead of a table view for this as it's easier to set up all the fields in the row as a button that way. In table view you ahve to use script triggers to respond to a click on the row of data.
Either way, the script might look like this:
Set Variable [$ID ; CurrentTable::PrimaryKey ]
Go to Layout [//layout for other table]
Set Field [OtherTable::Field ; $ID]