Translating Theme
Reneva theme is translation ready. I assume your WordPress is already in your language. If not:
- Go to: Dashboard > Settings > General and change the Site language.
There are three ways to translate it to your language:
Method 1 - using Loco Translate
Install plugin Loco Translate. After successful installation go to Loco Translate -> Manage Localization, you should see this screen:
Click New language, select your language and click Start Translating.
Now you should see that screen where you can translate each string that is used in theme:
When you're done, click Save, and you can also click both "Po" and "Mo" buttons to save them on your PC as a backup.
Method 2 - using Codestyling Localization
Install plugin Codestyling Localization. After successful installation go to Tools -> Localization, you should see this screen:
Click Themes (if you'll see any timeout errors etc., click the 'enable low memory code' checkbox) and find Holomatic on the list:
Here we already have English and Polish version
Now we can add new languages, let's add German. Click Add New Language, in the popup find 'de_DE' and click "create po-file'.
German language should appear on the list. 
Click Rescan button and than 'Scan now' in new popup. After that you can click Edit on the list.
This how it should look now:
You can translate here every string that comes in the theme, and after you do it click Generate mo-file
There's a notice message on the top:
Warning: The actual loaded translation content contains mixed textdomains and is not pure translateable within one textdomain. It seems, that there is code contained extracted out of other plugins, themes or widgets and used by copy & paste inside some source files. The affected unknown textdomains are: woocommerce, option-tree
All strings that are from WooCommerce textdomain will be translated automatically if your WooCommerce is in the same language as you set (so German in this example). Read more about WC localization - Translating WooCommerce
Method 3- using PoEdit
Download PoEdit and run it.
Click ' Create new translation', navigate to holomatic/languages, and select en_US.po (you might need to switch filter on the browser from *.pot to *.po). Select your language"
now you can translate one by one each string from the theme, after you finish (you don't need to translate everything, save the file as for example fr_FR.po, not fr.po like PoEdit suggest. That should generate two .po and .mo file.
Making your Localization upgrade safe
Keep a backup of your translation in safe place, as WordPress might remove files during auto-updates, and you probably wouldn't want to lose it :)