Here are your controls and their definitions:
Enable Hammer Ons - This switch will toggle Hammer Ons to be active or inactive. When it is positioned to OFF, Hammer On Mode will disabled. The jamstik+ comes default with this turned on after the update to firmware 5.034.
Hammer On Timer x 10 milliseconds - The amount of time Hammer Ons / Pull Offs are allowed to occur after a note is played. This function will reset after each note is triggered.
Hammer On Velocity On/Off - This setting normalizes the volume of HO and POs. Tries to determine intent based on speed of your fingers. We recommend to leave this ON.