Additional sign in dimension
The number before the hole diameter specification tells you how many holes there are of this type. It is up to you to then spot where those holes are. For example, 4 - ⌀3.5 PTH is telling you that there are 4x 3.5mm diameter Plated Through Holes - in this case one at each corner of the LCD.

Please note that there is a mistake in this datasheet, as 10 holes are specified for the connector at the edge (10 - ⌀1.0 PTH) but 12 are shown and labelled.