The actual activation of the Standard Point Buy involves only a couple of steps, though they may not seem immediately obvious. First, open up the Character Configuration menu by using Config->Character Inforation. Second, scroll down to "Custom Points" and open up the individual item.
Stat Points are listed in the grid for the Custom Points, by default as the second appearance. Scroll to the right, to the Column labelled "Activated" (The 8th column). Double-click the text "No" and it will become "Yes", meaning that now the Custom Point is active.
By adjusting the amount of points that a character receives at creation, a campaign can be made more powerful, or less powerful. Characters may become more or less average, depending on the power of the campaign.
Scroll down to "Custom Points Method" in the Character Information configuration, as above.
At the top of the page is a drop-down list of all the "Custom Points" in your configuration. Select "Stat Points" from this list, and a list will appear. Simply adjust the fourth colum, "Modify" to the amount of Stat Points you wish characters to start with for your campaign.