Please follow to these steps for making translation of the wordpress plugin. In our case we are explain how to make it for the Booking Calendar plugin.
1) Before making translation of wordpress plugin, you need to have POEdit application. You can download it from here. Its completely free. Please install this application.
2) Now please download the Booking Calendar plugin. You can download it from the WordPress directory, from here.
Please extract the archive of the Booking Calendar plugin. Inside of the Booking Calendar plugin folder you can find this folder: "languages". Its folder, where are list of all available translations of the plugin (let say the path to this folder is "../booking/languages/" ).
3) Now start the POEdit application. Inside of the menu select File > "New catalog from from POT file", and select the wpdev-booking.pot file inside of our "../booking/languages/" folder, where you are extracted the booking calendar.
4) Type the description of your translation in the new popup configuration dialog.
5) Now in the "Save as" dialog, please type the name of the new translation file, in format: "wpdev-booking-LOCALE.po", where LOCALE - its locale of your new translation. In other words, the name of file consist from 2 parts: 1st part its filename of the plugin (in our situation its "wpdev-booking"), 2nd part its the locale (for translation in Spanish language "es_ES"). For example for the German translation, you will have the name of file like this: "wpdev-booking-de_DE.po". Save this file to the "../booking/languages/" folder.
6) Now please make the translation of the each term in the "Translation" field. If you find in translation “%s” symbol you shoud leave it at the same place as at original translation line, its system variables. Please be sure that you are unchecked the "Fuzzy" button at the toolbar (or at the Edit menu), otherwise the translation will not apply to the plugin.
7) Save the file (Using the file menu File > Save). Inside of the "../booking/languages/" folder you will see your 2 new files with extensions "po" and "mo".
8) If you made new translation or update the exist translation, you can send this translation files (*.po, *.mo) to info @ wpbookingcalendar.com and we will add them to the next release of plugin. Thank you.
If you are made update of the exist translation,
inside of the step #3 instead of creation new file, select File > Open menu and select the specific PO file in the "../booking/languages/" folder.
Then follow this instructions from the point #6.