Start with pencil on 15 degree mark at the bottom
Line goes vertically to a point about one third the way between SL and 2000 lines
Go horizontally across the chart from that point to 2950 lbs which is just the reference line in this case
Continue across to the head wind speed (9kts in the example) and here kink your line to parallel the drawn line below until you reach the correct speed.
Now the tricky bit which isn't shown well on the diagram.
Track across horizontally to the far right and read ground roll distance, 1375 in the example,
Then go back to where your line crosses the zero reference line and follow the diagonal line to read the 50 ft clearance distance, 2300 ft in the example.
Hope that helps