Please teach me how to import Kakao API I keep getting errors

You need to check the build.gradle file to see how you configured the development environment. In the gradle environment of Android Studio, you can add Kakao SDK as follows:

App Module build.gradle

repositories {
    maven { url 'http://devrepo.kakao.com:8088/nexus/content/groups/public/' }
}

...

dependencies {
    compile 'com.kakao.sdk:usermgmt:1.1.35'
    compile 'com.kakao.sdk:kakaolink:1.1.35'
    compile 'com.kakao.sdk:kakaotalk:1.1.35'
    compile 'com.kakao.sdk:kakaonavi:1.1.35'
    compile 'com.kakao.sdk:kakaostory:1.1.35'
}

I have confirmed that it works well in my environment, so please add the above code.

Refer to Configure Development Environment > Use in Gradle Environment in the following link for more information.