Hi,
There is no question, thus I assume you just want general inofrmations:
Use a non inverting OPAMP circuit.
Gain: according input voltage range of the MCP3918.
Gain setting resistors: anything between 1k and 10k will give good results.
Read the OPAMP datasheet regarding ouput voltage range. If you want to measure voltages very close to 0V then the OPAMP may need negative supply voltage.
I recommend a 100R + capacitor LPF between OPAMP_ouput and MCP3918 input.
Capacitor value depends on the expected signal bandwidth.
Klaus