Do I need to add answers to the reviewers’ comments to a conference paper?
It's unclear from these instructions whether a separate response document is required by this program committee or not. However, it's easy to write one, and it will make it very easy for the PC to see that you have addressed the reviewers' comments. You should prepare a short separate document that lists each reviewers' comment and the action (if any) you have taken to address it, referring to pages, sections, or figures that have been modified. Depending on the submission system, you may be able to upload this as a PDF or incorporate it directly into the submission system in a comment to your final submission.

Not every comment will lead to an action on your part, so if you disagree with a comment and made no change based on that comment, you can address why in your response document. Sometimes, you will write your reason for not making a change, realize that your reason could be incorporated as a clarification in the paper itself, and then make that clarification instead (and note it as such in your response to reviewers). Thus, preparing the response document and addressing each comment point-by-point, can help you figure out how to deal with each comment and lead to a better article.

You should prepare at least the outline of this document even if, in the end, there's nowhere to submit it. If you're having trouble finding a place to upload it, you should ask the PC Chair or whoever is shepherding your article whether they want your formal response.