I started with implementing the desired circuit with eSIM tool. 
Then I created a netlist. As I enrolled myself in one of the previous esim events,
it was easy for me to design circuit using eSim but implementing skywater 130 parameters was bit confussing at the first
eventhough we are provided with reference videos. Then I began to research quite deep with these stuff and it became handy for me.
Then it was quite simple to run the modified netlist with ngspice and at first I didnt get the desired outputs(sum and carry) 
as I used the digital input volatges as 1.8V (which was mentioned in 2 bit DAC course) and I tried differnt things as I dont know was causing this. 
and at last came to find and converted to 2.2V and the output was fine.This event has taught me a lot in the area of CMOS and I believe it will 
be helpful in my upcoming academics and for my future.