I am trying to import a cvs file and what operator do I use to eliminate unwanted columns?
The data import can be done via two different ways: using the import wizard into the repository (preferred way, check out this: http://docs.rapidminer.com/studio/getting-started/2-importing-data.html) or by using the operator Read CSV (http://docs.rapidminer.com/studio/getting-started/3-data-loading.html). Both videos show examples for Excel but CSV works in principle in the same way.
For removing columns, you have again two options: Select Attributes (http://docs.rapidminer.com/studio/operators/blending/attributes/selection/select_attributes.html) can be used to manually select which columns (called “attributes” in RapidMiner). You can keep (or remove) single columns or subsets which is defined in the parameters of the operator. The second option is Remove Useless Attributes (http://docs.rapidminer.com/studio/operators/blending/attributes/selection/remove_useless_attributes....) which automatically removes useless attributes for you, i.e. for example columns which only have one single value.
In general the following video series might be helpful: http://docs.rapidminer.com/studio/getting-started/
You also should definitely check out the built-in tutorials which can be found under “Questions” in the top right corner of the product.
Last but not least: these are the type of questions our user community is more than happy to help you with as well. You can find it at http://community.rapidminer.com