Hi surjit,
Start with trying the 2D tutorial at :
Defining Materials for the MMI Coupler
This will guide you in the correct way for creating and placing elements, it should be a simple step to change the waveguides to optical fiber waveguides, using the Profile Manager.
After you have created the correct layout of your design the first graph should automatically be created from the output of the simulation. To include information of the normalized power in the simulation you need to change a few options. If you follow the tabs to Simulation ->Additional Output Data you can include more data in your simulation (e.g. Power vs. Propagation Distance).
I have attached a section of the User Reference that explains these options.
Regards
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