The first thing you must do in order to use Jitsi Meet API is to initialize JitsiMeetJS object:

JitsiMeetJS.init();

    Then you must create the connection object:

var connection = new JitsiMeetJS.JitsiConnection(null, null, options);

    Now we can attach some listeners to the connection object and establish the server connection:

connection.addEventListener(JitsiMeetJS.events.connection.CONNECTION_ESTABLISHED, onConnectionSuccess);
connection.addEventListener(JitsiMeetJS.events.connection.CONNECTION_FAILED, onConnectionFailed);
connection.addEventListener(JitsiMeetJS.events.connection.CONNECTION_DISCONNECTED, disconnect);

connection.connect();

    After you receive the CONNECTION_ESTABLISHED event you are to create the JitsiConference object and also you may want to attach listeners for conference events (we are going to add handlers for remote track, conference joined, etc. ):

room = connection.initJitsiConference("conference1", confOptions);
room.on(JitsiMeetJS.events.conference.TRACK_ADDED, onRemoteTrack);
room.on(JitsiMeetJS.events.conference.CONFERENCE_JOINED, onConferenceJoined);

    You also may want to get your local tracks from the camera and microphone:

JitsiMeetJS.createLocalTracks().then(onLocalTracks);

NOTE: Adding listeners and creating local streams are not mandatory steps.

    Then you are ready to create / join a conference :

room.join();

After that step you are in the conference. Now you can continue with adding some code that will handle the events and manage the conference.