Orthodox Jews believe in the literal interpretation of the Bible and the static, unchanging quality of Biblical ordinances. They provide the most historical and traditional foundation of Judaism. It's Orthodox Jews who still make the path to conversion, for example, long and challenging, taking a couple of years, and mandating study, circumcision, the ritual bath, etc.
Ultra-Orthodox Jews are basically Orthodox Jews who believe in restoring the literal law of the Bible, and living Biblically. For example, Ultra-Orthodox Jews believe in resettling the disputed territories because they're really Judaea and Samaria, and are prepared to face even the Israeli military for the right to live in a tin hut on a piece of land most meaningful to them.
Orthodox and Ultra-Orthodox Jews have the same beliefs, but Ultra-Orthodox Jews take them to a higher level, with a bit of fanaticism.
Conservative Judaism is a movement that began in the 1800s in order to adapt religious Jews to more modern values. Conservative Judaism embraces the foundation of Jewish values, but does not insist on their literal interpretation as opposed to their historical interpretation, and accepts the possibility of a lot of adaptation and swerving from the foundational rules. In short, Conservative Judaism is basic but flexible Judaism.
Reform Judaism is wholly reconstructive Judaism. It does away with many of the old ways and rules altogether. Reform Judaism aims to revolutionize the structure, laws and interpretation of Judaism to make it a completely modern religion. It's the smallest sect of Judaism, with under 1 per cent of Jews.
Conservative and Reform Judaism make conversion much easier.
A secular Jew is someone who identifies as Jewish, perhaps because they were born to a Jewish mother. However, a secular Jew may see the Jews as a race, history, culture and civilization, and see the Jewish religion as only one part of that whole set. So a secular Jew feels they can authentically call themselves Jewish without believing in the Jewish religion, the same way an ancient Greek or Egyptian could still be Greek or Egyptian without believing in the pantheon.
Your additional questions are too much effort.