Click on HKUST -> Tape out -> CIF in the layout window as shown below.

The CIFOut form appears.
After you fill in the form. It should look something like this,
When you are done, click on OK.

After a moment, CIW should read "There were no error or warning messages" and "NORMAL EXIT" as below.
Always take a look to the log file to see whether there have error/warning messages.
The CIF file can now be found in your current working directory.
Repeat above steps for remaining layer(s) of your layout. again.

File Retrieval by CIF In (Verification).

To verify your CIF file you can convert back to Cadence by CIFIN.

Select Translators -> Physical -> CIF In in the CIW and the form appear. Just fill in:

Input file name: <CIF filename>
Library name: verify

Inportent notes: DON'T use the orignal library name for CIFIN. You orignal library will be overwrite if you do that.
Click on OK when you are done.

Then the layer contains in the CIF file will be transformed back to a layout in the library verify.

Check to see whether there have error or warning messages in CIW.
After CIFIN. Select Library Path -> Refrash in the Library Manager.
Open the layout in the library verify.