How to create a session using jsoup and how to post the data using jsoup

I can't create a session using jsoup and how to post the data using jsoup. Please help me, I'm new to jsoup api, actually my code is:

Connection.Response res = Jsoup.connect("https://wiki.my---------------")
    .userAgent("Mozila")
    .timeout(0)
    .method(Method.GET)
    .execute();

Document docu = res.parse();
Map<String, String> cookies = afterLogin.cookies();
Document doc2 = (Document) Jsoup.connect("https://wiki.my------------------")
    .data("os_username", "A57", "os_password", "pass")
    .data("login", "Log on")
    .cookies(cookies)
    .timeout(0)
    .post();

I get one webpage (doc2)and then add to some table to that webpage (doc2)?

How to add new data already existing web page doc2 and then how to post doc2 to anther url. Already tried a lot, please help me.