You should follow the general design of the Arduino current sensor that is described in the ‘Learn’ section here. I do not know what the capabilities of your particular ADC are, but there are two important parameters, the input should be sensitive enough so that the c.t. you intend to use operates within its VA rating, and the sample rate should be high enough to give you at the very least two samples per cycle at the highest harmonic of mains frequency that you’re interested in. As a guide, the Atmel328P takes an input of around 1 V rms at maximum current (lower would be better), and runs at around 100 samples per cycle (5 k samples per second).
The optical pulse sensor from the shop actually has an overdriven analogue output - everything we know about it is either on the OEM Shop website or in ‘Resources’ here.