How to put a Spot Trailing stop sell order ?

Hiya.
I'm making an attempt to place an trailing stop sell order on spot, however I don get it.
This explanation could be very dangerous. The image could be very confusing (to me... ).

I'll try to make an instance of my drawback .

Suppose that the current worth of ETH is 3950 usdt.

I put the order with this parameters:

Limit: 3850
activation: 3820
trailing delta: 1%

On this case, seems a sell order at 3820. This order is just not shifting.

What I'm doing mistaken?

Thanks.