@jstap The minus sign and the multiplication sign cannot be typed in the name of the constant

This is my revised one, and I'm not sure if my understanding is correct.
https://fxdreema.com/shared/ZYhUzz9U

Probably because of the network, I can't see the image I uploaded before, and this image is the expert I want to write

Maybe it's because of the Internet, I can't see the picture I uploaded before, this picture is what I want to write and can only be traded .

@jstap Thank you so much for your help, I'm going to give it a try now

@l-andorrà Thank you very much for your help .I wanted to write about such an Expert Advisor. At the price of 2294 buy0.01, when the price falls back to 2290 sell0.03, the price returns to 2294 buy0.09, and so on, until the profit is closed.But it didn't turn out what I wanted
I don't know if my logic is correct, below is the link, please help me to see, thank you very much https://fxdreema.com/shared/VVkbSwikc

I don't know which module is needed for the calculation of the next lot value below the buy and sell block

Is that so?