You should not need to do anything extra to have the react-native-vector-icons library installed for Android since React Native link should have taken care of the entire process for you.
However, if you decided to link the library manually for iOS, the readme file for react-native-vector-icons has the latest, up-to-date instructions for importing the library manually for Android devices. As these instructions can change with newer releases to the library, I heavily recommend you follow them directly from the README file.
If you already have the package installed in your project's node_modules folder, you can read the instructions from there without requiring further Internet access.
The instructions on importing ...