In order to set up Magento 2 Auto Language Switcher Module please go to Stores > Configuration > Magefan Extensions > Auto Language Switcher.
Make sure if the extension is enabled choosing Yes in the Enable Extention select box.
In User Agents you can set the user agents (bots) this module will be disabled for. E.g.: for Google bot, this module will be disabled, it will crawl the site as usual.
Default Store View By Country
In this section, you can configure language switcher by country.
Select a region and country you are interested in and set default store-view for it. You can leave default settings to detect store-view based on customer browser language.
Once all of the configurations have been finished don't forget to press the Save Config button and Flush Magento Cache.