Urgent need for help- Designing a transconductor circuit and 2nd order voltage-mode low-pass filter

Here is my question about how to design the circuit in the attached file.
How can I design the transconductor circuit and 2nd order voltage mode low pass filter, using the designed circuit in the first step.
Mainly I want to know how to design the circuit for Vbias and Iref??? Should I design the MOSs with different W, Ls?
I need an urgent help for this homework as I have to deliver it on 25th!!!!

Thanks a lot!