Copy A6 card design to an A3 then copy paste to fill (Affinity)

Paul Apps

New Member
Copy a full card design say in A6 to a new document say A3 preserving all layers and outer dimensions. then to copy and paste the A6 as many times as will fill an A3
many thanks
new to Affinity and struggling a little
Also when I have an A3 open on an Artboard, If I copy and paste an A6 onto that A3 without an Artboard, it comes in as a new Artboard and not a layer. how do I overcome this as I cannot see artboards collectively unless they are layers?

Any help please make the explanation step-by-step and idiot proof thank you in advance.