Fatigue loads defination in abaqus

Dear Sir/Madam,

My name is Muhammad Imran and I am working on experimental fatigue life calculation of aluminium-silicon alloy and validation of experimental results with abaqus fatigue results. The fatigue simulation is totally new topic for me and I don't have any idea how to apply fatigue loads in abaqus. 

During fatigue experiments, 100MPa (constant amplitude, sinusoidal) stress is applied at 20Hz frequency which led to specimen failure after 268220 cycles. I want to input these parameters in abaqus.

I would be grateful to you if you can guide me how to apply fatigue load in abaqus. I Know this can be done by using "amplitude", but I am not getting the desired load waveform.

Thank you!

Best Regards,

Imran