Hello,
Regarding your query, actually you have to add all the plugins recommended by the theme.
Further, you can get option of “Testimonial” in the admin panel after you add the recommended plugins.
https://prnt.sc/vekli4
You can add testimonials as per the requirement. This will help you display the testimonials in frontpage.
Please refer to the documentation link given below:
https://themepalace.com/instructions/themes/corponess-pro/#doc-testimonial-22
Hope this helps.
If you have queries further, kindly let us know.
Regards.