Here's a mermaid flowchart block diagram incorporating the 3 buttons, 1 potentiometer, IRFZ44N, and limit switch:
Diagram
This diagram shows:
A 12V car battery powering the system and going through protective circuitry.
The control logic receiving inputs from 3 buttons, a potentiometer (which disables the buttons when active), and a limit switch (to disable the piston when its end is reached).
The control logic then drives the IRFZ44N which controls the hydraulic piston.
You can now use this diagram as guidance for your design within Flux.