I have an layout based on table1, table1 have one related table, called table2, and table2 has a related table called table3. How could I show a portal with the table3 records on the table1 layout? Illustration attached
On a layout based on Table 1 you can create a portal based on Table 2. Since Table 3 is related to Table 2 along the same pathway you will also be able to included Table 3 fields within your Table 2 portal.