Many of the settings are identical to xpBullet Rigid Body and illustrations for them can be found in that page.
xpBullet Soft Body tag Dynamics tab menu settings.
Checking this box enables the tag.
If this box is unchecked, the object to which the tag is attached will not be checked for collisions with any particles.
Set as Soft Body, by default, this changes the type of dynamic system being used.
The other options are: Collider and Rigid Body.