How does Clicermann work?

Question

Macros

I want to write a small code for the Minecraft game, namely working with Clickermann, here's the idea:
GETSCREEN
IF_PIXEL_IN (heart coordinates, heart color) - when the color that I wrote down is in this place, the following command will be executed:
KEYPRESS (# 3)
RLICK()
KEYPRESS(#1)
How can I do this? I write everything correctly, I go into the game I activate the script, nothing works
Here is the script itself (Playing in full screen mode):

GETSCREEN
IF_PIXEL_IN(heart coordinates, heart color)
KEYPRESS(#3)
RCLICK($_xmouse, $_ymouse)
KEYPRESS(#1)