What Software does the participant need to do the interaction E-Learning?

Your participants shouldn't need anything other than a browser, ideally an up-to-date version. If it is an older browser, the participants will need Flash plug-in installed.

You need to figure out how they will access the presentation (server, website, LMS).

Video based files, by themselves, do not include any interaction--you need to publish as HTML5 and/or SWF.

The cptx file is your Captivate project file. This is what Captivate will open so you can continue to work on your project or make changes.

This is not what your learners will interact with.

When the project is finished you will need to publish it. You can publish as SWF or as HTML5 and then upload them to some type of web server or LMS. If you are using an LMS, you may want to publish as a SCORM compliant zip file.

Pretty much all your learners need are up to date browsers

Have a look at the Captivate system requirements for Content Playback listed here: https://helpx.adobe.com/captivate/system-requirements.html 

Did you create this simulation with Adobe Captivate or some other program?