@User Thanks for the suggestions again. But in case of the step " redo make install " i had to again do "sudo mak install" as it was showing make erros in the former case.
@User I watched a video tutorial of plotiing VTC of an inverter on by you where you are using "madvsi" library of the models which contained tt_models, sf_models, ss_models, fs_models etc. I copied the directory "madvlsi" into "/home/rahul123/share/xschem/xschem_library/" and now when I lauch xschem (using xschem -b & ) from either home or from "~/.xschem/xschem_library/xschem_sky130/" , there are two libraries for inserting the symbols, to create a schematic, which are " devices" and "madvlsi". I followed the instructions as demostrated in the video (the link is pasted below) but as shown in the video when I click on the button "netlist" it creates a netlist in the directory "~/.xschem/simulations". But when i try to open the netlist from the xschem window it does not open. In the menu bar of xschem, there is a menu "simulation" ---> "edit netlist" but it is not popping out the netlist. It is neither simulating the design as shown in the video nor showing the resulting waveforms. Please help me to deal with this situation. I am stuck in between. Thanks & Regards Rahul.