K8015 connection to and use transient suppressor

I’ve 2 questions:

1: connection to part SK4. There are 3 entrances, are only the two at the right side to be used, and are they both for high or low voltage? (not in the same time of course)

2: I don’t understand the use of the transient suppressor. When open, when close? Or when omitting at all the jumper?

thanks for answering me.

SK4: use either common - normal open or common - normal closed contact.

SK1: depends on contact used. Omit jumper for small loads.