Work out the multiplication and division first: 36÷5*1=36÷5=7.2; now put this into the expression:
7.2-4+9+3-18+6. It doesn't matter what order you use now because add and subtract have equal priority, but it's probably easier to group the positives and negatives together. So the positives are 7.2+9+3+6=25.2 and -4-18=-22. That gives us 25.2-22=3.2 as the final answer.
If the question had been 36÷(5+1)-4+9-18+6, we would have had:
36÷6=6 then 6-4+9-18+6=6+9+3+6 and -4-18; 24-22=2 (PEMDAS), where parentheses take first priority.