no, you don't, the breakers more or less press fit...

make sure you are comfortable with what you are doing and it makes sense that it is safe to you...

I should add when I say it is surely cold its not connected to supply anymore was wrong, if there was another point in the circuit that you cannot see and the circuit is connected to supply at that point... this would certainly cause trouble so it is best to verify it is cold before touching it regardless.

the steps are simple enough, but overlooking one of them could be dangerous.

understanding how it is safe is the best.