Please take care that the download files are shown in front-end only in the case, when they are assigned to the existing category. The file status "published" in the File List table is therefore not sufficient to display file in the front-end.
After the installation you can select language sets in Administrator Extensions->Language Manager which you like to prefere as default (take care for Site/Administrator tabs to select which part of Joomla presentation you like to change). With described change is automatically changed also language set for JotLoader component.
For site front-end you can use any possible language set (included in UTF-8 coding) for your presentation of download files with proper JotLoader settings in Administrator. Only Bug Tracker functions & buttons shall remain in basic language set (easy to omit Bug Tracker when you like).
Set up your preferencies and settings for this component (Components->JotLoader->Settings, see JotLoader Settings). Then select in Joomla Administrator proper menu set to which you like to assign the JotLoader content (usually is selected Menu->mainmenu, see JotLoader Menu).
For uninstallation of JotLoader component please select via Joomla Administrator Extensions->Install/Uninstall->Components link and set JotLoader radio selection to "ON", then press Uninstall button in the toolbar. Database tables of JotLoader will remain intact with the last saved content.