Their best, dressy clothers.
The same way Jews in all other countries do.
They wear nice clothes which they have specifically designated for shabbat.
yes for ordodox and ultra-orthodox jews reform jews might adapt the rules of shabbat
No, that violates the Shabbat.
Fewer Jews are observing the Shabbat laws.
The Shabbat is observed by all Jews, both men and women. However, it is the women who traditionally light the Shabbat-candles.See also:Women and the lighting of the candles
Shabbat Shalom is a greeting that Jews say to each other on Shabbat (the sabbath). It means "A peaceful Shabbat"
they rest for the day
Shabbat
No, Orthodox Jews do not use phones during Shabbat except for major emergencies such as someone's life being at risk.
Orthodox Jews live in Australia, so they observe Shabbat, too.
Because for 3300 years the Jews have kept the Torah-tradition of Shabbat-observance.