Which operating system?
I have experience with Intellij and AndroidStudio but not VisualStudio.
Intellij - import Processing core library On MacOS it’s found in the app bundle at Contents/Java/core/library
Android Studio - copy processing-core.zip which on MacOS is at Documents/Processing/modes/AndroidMode. Change name to processing-core.jar.
One of the links is here: https://android.processing.org/tutorials/android_studio/index.html
Recent thread: https://discourse.processing.org/t/how-to-load-an-image-in-android-studio-using-a-processing-sketch/35860/2
Intellij reference: https://andrewmagid.com/Processing4-Java-IDE-Setup/