WPJobus theme recommends the following plugins: LayerSlider WP, Nextend Google Connect and Nextend Twitter Connect which are obsolete and not available instead those are now merged into a single plugin Nextend Social Login and Register (Facebook, Google, Twitter) which WPJobUS doesn’t support causing the theme unusable. Need help at the earliest please.
WPJobus theme included LayerSlider and may be they will recommend Nextend Social Login and Register (Facebook, Google, Twitter) which is free. So I strongly recommend please read the theme documentation first and follow their installation process and hope you will also get how to install all recommendation plugins. Still you have any query with theme then the best way to get support is contact theme Author.