Now that you've exported your references from Refworks, you need to import them into Zotero:
If you've selected the new collection option, Zotero will put all the imported references into a new folder named for the filename of the RIS file. (If your file was named export.ris, look for a new folder in your library called Export.) You can rename this folder, especially if you will be exporting one folder at a time from RefWorks to preserve your RefWorks folder structure.
If you are importing each folder one at a time, delete the export.ris file and then repeat the process in RefWorks for your next folder.
If you have articles in RefWorks that you received via interlibrary loan or would be otherwise hard to replace, you may want to download those PDFs or other files from RefWorks.
If you'd like to have the PDF or other file paired with the reference in your new Zotero library, you may drag and drop the PDF onto the reference in Zotero.
Once dropped onto the reference name, you will see the file nested under the reference entry.
Right-click on the PDF and select "rename file from parent metadata" to give the PDF a human-readable filename that matches the reference.