Plugins bundled into theme, like: Slider Revolution, Layer Slider or WPBakery Page Builder, could be easily updated from Betheme > Install Plugins section.
If new version of the bundled plugin is available, you will notice currently installed version marked with red color, new version number will be green color and under the plugin name, the Update button will appear. All you have to do is click the Update button and the process should begin. In some cases it may take up to a minute or two as it depends on hosting.
Notice!Layer Slider plugin requires its deactivation before the update. In that case, you have to go to Plugins > Installed Plugins section, find the Layer Slider on the list and click Deactivate button located just under its name. When the update is finished, you can activate the plugin again. No worries, you will not lose any settings or content due to plugin's deactivation.