Step 1

Navigate to the "Settings / Language Switcher" section of your langify backend:

Step 2

Select the theme you want to edit the language switcher for.

Step 3

If you scroll down a bit, you will see the "Select a language switcher" section.

Simply click "Select" next to the switcher you wish to use.

Note that you can change the width, position, etc. via CSS as explained here: http://support.langify-app.com/support/solutions/articles/1000186503.