The line is a visual depiction of the rate. Straight across is 0s, heading down, losing, heading up, gaining. A solid line means the watch is perfectly in beat, a double line is out of beat, with the spacing relative to how much beat error there is.
You should ask Witschi for a manual if you don't have one; here is a link to their "training course" with all you will need to know (used to be on their website but not anymore).
Play around with your machine in the meantime: it should be set to "aut",, so it detects and sets the freqency, or "man" where you tell it the frequency. There you have it set to frequency, so it isn't giving you what you really want here- that watch's frequency is 21,600.
https://www.welwynwatches.co.uk/uploads/9/1/4/3/9143536/witschi_training_course.pdf