You can put data from multiple tables onto a layout but the issue becomes how those fields relate to the POV (point of view) of the current layout.
If the relationship to the current layout is one to many (ie for 1 record in the current layout there are multiple key matches in the related table) will probably want to put a portal on your layout and then put the fields in it. However if all you want to do is show the most current info in the related table you can just define the relationship to sort decending and just place a related field on the layout directly.
It really depends on what you want to show and finding the right POV that has all the connected keys to show the information you want.
List and Table layouts are also useful for showing multiple records in the current table.
The key here is in getting the correct POV and making sure all the relationships you need are established.
Thank you for replying. Is there a tutorial for a database that includes, Products, Quotation, Invoice and Customers tables that are all related. I'm really struggling on my first project and if I had a suitable tutorial I could pull it apart and see exactly how it works it would get me underway.