Thanks.
From the datasheet i can see the dimensions but the placement from the origin is kinda confusing.
In the datasheet attached, the placement of the main pad which is 8.00 long and 3.99+0.50+0.85=5.34 high. Are coordinates for these mentioned as y=4.05, x=1.29 ? how is the grid set ? In the tutorial mentioned here. The author uses a formula but not clear on what it is based.