how to tile in indesign
tiling is a way to print a larger format document with several A4's or A3's

create a new file in indesign
make the file exactly the size that you want for example 1000 x 1000 mm
the original document should be the same size for for example 1000 x 1000 mm
in the menu go to file, place
select your document
this file needs to have the same size as the indesign file you made, in this case 1000mm x 1000mm
the picture is ready to be tiled
select print, choose the printer you want to print to
go to set up and check the tilebox. choose the overlap that you need. in the printer menu choose the settings that you need, then press print.