Hello,
1) Choose the necessary RTL language in the WP settings to enable RTL styles http://prntscr.com/s46qet
2) Follow the Dokan plugin docs to find the necessary shortcode to display vendors https://wedevs.com/docs/dokan/getting-started/dokan-shortcodes/
We are not plugin developers, we are theme developers and are able to guide you about theme options. To get help with plugin options contact plugin author.
Regards