Hi,
yes, there are two ways to do it you can either use the Custom Fields extension https://wpadverts.com/extensions/custom-fields/ to limit the file uploads or if you have some PHP programming knowledge you can use the Limit File Uploads snippet https://github.com/simpliko/wpadverts-snippets/blob/master/limit-file-uploads/limit-file-uploads.php
How to install the snippet you can read here https://github.com/simpliko/wpadverts-snippets/ at the bottom of the page, once you have it installed and activated inside the limit-file-uploads.php file you would need to set upload options to suite your needs.
In your case you will just need to change lines 41 and 42 to
"min" => 0, // minimum files to upload
"max" => 3 // maximum file uploads
other validators you can remove.
