it is like this;
"random integer number between 1 and 11 means that"= ANY NUMBER from 1 to 11, so it may a from of chance thingy
"Less than or equal to 1"= means like this; X < or = 1
So based on that trigger, that conditions means like this;
LET X = random integer number between 1 and 11
REP: X < or = 1
so it means that, IF X is any number and IT IS less than or equal to 1, the trigger RUNS
for example, X is equal to 1, and 1 is equal to 1 (lol), so that means the condition is correct, after that your "then-actions" will "RUN"
ahh damn i cannot explain it properly!
but i hope you got what i mean lol