You find that a table (e.g. swnewscategory) is missing from the database.
The newly installed app database table will only appear when the app is installed. The tables are only created in the DB during the app installation i.e. If the module is not installed, those tables will not be present. You would need to install the app by going to Admin CP > Apps > and Installing the affected app.
The strings responsible for generating the missing DB tables are nested in files under the <kayako_install_folder>__apps/<app_name>/models/ folder, which is the home folder. When the app is installed, Kayako creates the new tables in the DB. The tables are not coming with the out-of-the-box database if your Kayako is not pre-packed with the concerned module.
One other thing to consider is that uninstalling the app will purge the relevant DB tables. Therefore, if you ever encounter the situation of needing to uninstall the module, please make sure that you perform a DB backup first, as, after reinstallation, the relevant section (for e.g. News Section) will be completely blank, as freshly installed for the first time.