DSO Nano V3 and my waveform

probably silly problem but some days I’m thinking about it before sleeping.
I’m using DSO Nano V3 Fw 4.22 to study a signal 0.5÷4.5V, usually on 2.5V but when I act the mechanism it moves towards up or down.
The cycle od no load application of load and no load again is about 0.5S. I would like to study the waveform on the last time before coming back to zero.
I set a trigger threshold and sensitivity putting them in the middle of 0.5÷2.5V.
My problem is that I see the waveform but only on the screen while the system is continuing to store data “outside” of the screen. What I mean is that if I move the ViewPosi I can see the real waveform on the right. I move forward and when at the end I run back again.
In this manner I can’t study the wave during the functioning because I see the wave on the screen then a lot of time without seeing it then I see again for a while and so on.
I don’t neither understand the meaning of SmplDpth. I’m pushed to always put it on 1K but is it right or not?
Thank you.