Problem importing classes

[t-51]

Hello
I have a project and I want to use ics-openvpn in my project. I cloned it into my project and the address is as follows.
MyApplication/
├── app/
├── ics-openvpn/
Now in my project, I imported it in the main activity class as follows:
import de.blinkt.openvpn.core.OpenVPNService;
import de.blinkt.openvpn.core.ProfileManager;
import de.blinkt.openvpn.core.VpnProfile;

But the problem it has and the error it gives is as follows: Import above
Cannot resolve symbol 'core'

The general route is as follows:
ics-openvpn/
└── main/
└── src/
└── main/
└── java/
└── de/
└── blinkt/
└── openvpn/
└── core/
└── OpenVPNService.java

What should I do now to fix the problem?

[schwabe]

This project is not really meant to be used as a library. Problems using it as a library are expected and you will find your own solutions to deal with that. Also keep in mind that by using parts of this project, your app will be GPL and open source.

[t-51]

I understand what you mean. I just want to learn and I started this project solely for the purpose of learning.