When using iCopy design there are a couple of rules to follow.
The first thing to take note of is that iCopy works on adaptivity and skeletal modelling. Top -Down technique.
You need to create a sketch which will drive the model that you would like to copy, be it a part or assembly. This sketch needs to be made adaptive. We will call this skeleton.ipt.
Also note that the part of the model that you want to change, be it the width or the height needs to not be constrained via dimension or geometric constraint. This will lock up the model and not give it the freedom that the adaptivity lends it.
The next step is to create a part or assembly with the path(s) that the part or assembly is going to be molded by. We will call this path.ipt.
Think about a ladder that is wider at the bottom than at the top. The rungs (which is the icopied part) will start off wide at the bottom and get narrower as it travels up.
The next step would be to insert the skeleton part that you created into an assembly. We will call it iCopy.iam.
Please note that the skeleton.ipt and iCopy.iam should have their origin planes constrained so that everything is grounded and fixed. If it is not things can go awry.
An easy way to do this is when placing the part , right click and select ground to origin.
After insertion we author the part to work in the icopy environment by selecting points on the skeleton sketch which will follow the path(s) that were created.
I would suggest giving the points descriptive names so that you can easily tell which point0 son the sketch follow which path(s).
You need to also make sure that the skeleton.ipt is adaptive after placing into iCopy.iam.
Now that this is done you will test to see that the skeleton sketch follows the path.
If it does congrats, you have succesfully created your first iCopy design.