After enabling the Proportional Editing, you must choose a falloff type

from the options right next to the icon where you trigger the Proportional

Editing tools (Figure 4.33).

Figure 4.33 - Fallout types

By enabling a Proportional Editing and using as fallout type the

smoothing option, you can select a single vertex from a plane with

multiple subdivisions. Start a move transformation in the Z-axis with the

G key and Z key. As a result, you will get the surrounding vertices also

moving up (Figure 4.34).