Where do errors occur during error syndrome and recovery?

Each of the itemized steps specifies the part of a quantum circuit where a single error occurs. So, for that part of the circuit, essentially what you want to do is write out the circuit diagram. Then, you "slice up" the circuit, i.e. put in vertical lines that just subdivide the circuit into distinct slices where all the gates in the slice can be performed simultaneously. So, you know the number of time steps required, $T$ and the number of qubits involved, $Q$. So, the number of places an error can occur is $c_0= QT$.