1) Note which macro number you want to copy
2) Use windows explorer and go to the folder you installed UOA to, eg c:\program files\UOA
3) Then go to UOA-Settings\<account name>\<shard>\<character name> of the character with the macro that you want to copy from
4) The files that you want are the ones that starts with UOA-Macro*.
Eg if you want to copy macro one, copy "UOA-Macro1.cfg"
5) Then go to UOA-Settings\<account name>\<shard>\<character name> of the character you want to copy to
6) Paste