What is the procedure to determine the cell potential?

(N/A) Selection of reference electrode: The potential of an individual half-cell cannot be measured directly. We can only measure the difference between the potentials of two half-cells,which gives the $EMF$ of the cell.
$(b)$ Use of Standard Hydrogen Electrode $(SHE)$: To determine the potential of a single half-cell,it is coupled with a reference electrode whose potential is known. By convention,the Standard Hydrogen Electrode $(SHE)$ is used as the reference,and its potential is arbitrarily assigned a value of $0.00 \ V$ at all temperatures.
$(c)$ Calculation: When the half-cell is connected to the $SHE$,the measured $EMF$ of the resulting cell corresponds to the potential of that half-cell. If the half-cell acts as the cathode,its potential is positive; if it acts as the anode,its potential is negative relative to the $SHE$.