AJVoIP is a highly optimized SIP library for the Android platform. You will need to go trough the following steps to create your Android SIP client or to add VoIP capabilities into your existing Android app:

1. Download the Android SIP library and have quick read through it's documentation
2. You might load the sample project first and check its MainActivity.java file for a simple but working usage example.
3. Create a new project or configure your existing one (See the "Project configuration" in the documentation about the manifest/gradle config).
4. Add the SIP library to your project (AJVoIP.aar if you are using Android Studio. Otherwise use the jar file)
5. Import the package: import com.mizuvoip.jvoip.SipStack;
6. Create a SIP stack instance: SipStack mysipclient = new SipStack();
   then initialize it: mysipclient.Init(context);
7. Set parameters such as your SIP server address, username, password: mysipclient.SetParameter("serveraddress","voip.mizu-voip.com");
   See the "Parameters" chapter in the documentation for the full list of the settings options.
8. Use the SIP API:
   Make calls: mysipclient.Call(-1, “testivr3”);
   Send text message: mysipclient.SendChat(-1, "john", "hi");
   Use any other API (for example to send DTMF, set presence, call transfer, conference or other functions)
9. Check for notifications coming from the SIP stack. Adjust your state machine and GUI according the notifications received. See the "Notifications" chapter in the documentation for the details. (This might not be needed for very simple projects) 
10. Contact us if you run into any issue or with any question

All these are explained in more details in the AJVoIP documentation "Usage" chapter.