At first this Nomogram can be a bit overwhelming to look at. But don't stress I think you will pick it up quickly.
First you need to pick an altitude shift line.
Move from right to left to find the line that represents the number of meters you will climb in total, next
Move down the number of meters you will descend in total.
Follow this new line up and to the left (this is your altitude shift line)
see here we plan to climb 700m and descend 1000m
Next we keep going up the altitude shift line until we get to your estimated walking speed.
This is our pivot point.
In this example it is 4km/h
Now just draw a straight line from the number of Kilometers you plan to walk, through the pivot point till you hit the Hours axis. And voila you can read the estimated time.
In this example we will walk 10km and the answer is 4 and a half hours