To determine the size of the print file, do the following:

Substract the dimensions of the mat with the dimensions of any border. (If there is no border, you do not need to do this.) This is the cut size. Why? Read it here.
For the Patio quality, use a border size of 2,5 cm.
For Globossoft quality, use a border size of 1,5 cm.

Now add 1 cm bleed, this will ensure that your design fits nicely to the edge of the finished mat. Why? Read it here.
Stay 2 cm away from the edge with important elements. This will ensure that these elements will not be cut away. Why? Read it here.