How do I use Tasker to run a sync in FolderSync?

First of all the full version is required.

The full version works as a Tasker plugin - when you configure a new task in Tasker

you are presented with a number of Action categories, one of these being "Plugin".

Select this and then select "FolderSync" plugin action.

Then press edit and select the folderpair you wish to start syncing with this task is executed by Tasker.

Then save the task as you normally would in Tasker.

For a more general introduction to tasker go here:

http://tasker.dinglisch.net/faq.html