To get aquaiented with eSim I started building simple and basic circuit nand,nor and invertes. 
One thing a person should always remember rules check for circuit, by doing this we can anotate out schematics and also check the connections.
Next step is creating netlist which is with file extention .cir 
To model the circuit with sky130 we need to modify .cir file which is placed in project_name folder
This can be done my replacing mosfet_p and mosfet_n by model name which is included in "sky130.lib.spice"
To connect the project file and model file we need to inlude the path to creat connection
Now final sky130 netlist for the paricular project is created.
It is the time to create subcircuit. In eSim window click subcircuit icon, there click on new subcircuit.
Blank sch(schematic) page will be created here file->append schematics->select your schematic for creating subcircuit.
Once appending schematic is done annotate and click on library editor in tool bar. 
Now you land in another blank page where we going to create component for our subcircuit.
Click on file->current library->esim_subckt->ok
Now click on create new component and name the component and designetor.Then insert require pins to it.
Save the designed component in library.
They above process will be followed for creating subcircuit.
After creating subcircuit lets include it in out main CIRCUIT.
create netlist and modify it in such a way subcircuit file is included in netlist.
Inputs are given to the pins and output are polted in graph on running the netlist in ngspice.
NOTE:" pay more attention when giving a path to include some file"
NOTE:" give proper model name"

                                                                                                                          