How to prepare a huge printout 1000 X 3000 mm in Excel ?

Question

I have madea family tree where around 350 persons each is represented by a box (a shape) and all persons are connected with arrows - parents to children ect ect.

To be able to read data of each person from the box I think the print should be scaled so that each bos is 20 X 90 mm.

With that size of the boxes the total family tree will need roughly 1000 X 3000 mm.

I think I have to print it on 'a plotter' with endless role of paper somewhere in the city by a printing business.

But how can I prepare the print at home for that size of paper ?