Hi Antonio,
as Mary says Hot Potatoes is software that you install on your own PC, not on the
server. You can use the Hot Potatoes software to create interactive exercises. On the other hand, HotPot is commonly used to refer to the Moodle activity module which allows Hot Potatoes exercises to be administered via Moodle. At least that is how I try to use the terms
Once you have made an HP exercise on your PC, you can generate a "web page" version of it using the same program you used to create the exercise. The "web page" version is actually an html file, so you can save it on your PC and view it using your favorite browser. From what you say, you have already been able to do that.
You can also use the HP software to add images, sound files and even movies into an HP exercise. To add an audio player to play a sound file into your HP exercise, you open the exercise in the HP software, and select the "Insert -> Media Object" menu option. Then click the "Browse" button and navigate to the sound file (for example you might have a sound file saved in mp3 format), and click the player you want students to use to view the media file, e.g. "Add Windows Media player". Finally click "OK" and some html code will be inserted into the exercise which will tell the browser what sound file to play and what player to use to play the sound.
All this can be done on your PC, and I suggest you try that now and make sure you can view the resulting exercise in your browser and play the sound OK.
Once you have got that far, you are ready to upload the "web page" version of the quiz and sound file to Moodle. As Mary says, you upload both files to the "Files" area of the Moodle course.
Now you can add the exercise to your Moodle course by selecting the "Hot Potatoes Quiz" option on the "Add an activity" drop down menu in the section (=week or topic) of the course where you want to add the HotPot.
One common "gotcha" at this point is that the HotPot module is disabled by default, so if you can't see it in the "Add an activity" menu, you will need to enable it from the "Site Administration" links (Modules ->
Activities -> Manage activities) on the Site page
If you need further help, please let us know
Gordon