Summary of the laws of Shnayim Mikra which are elaborated below:
One is to read Shnayim Mikra Echad Targum on Erev Shabbos [immediately] after midday. Prior to reading Shnayim Mikra one is to cut his nails. One reads each Pasuk twice and then immediately reads its Targum, prior to moving on to the next Pasuk. One is not to interrupt at all, even to talk, until he completes the entire reading. After the reading one is to immediately read the Haftorah of that week and in a case that there are two Haftoras both are to be read. After completing the reading one immerses in a Mikveh.
In addition to the obligation to hear the reading of the Torah every Shabbos one is also obligated each week to read to himself the weekly Parsha in the form of Shnayim Mikra Echad Targum as will be explained next.
Are women obligated to read Shnayim Mikra?
Is a mourner/Avel allowed to read Shnayim Mikra?
Although a mourner is forbidden to learn Torah throughout the seven days of mourning, including Shabbos, nevertheless he is allowed to recite Shnayim Mikra Echad Targum, on Shabbos. He may not read it before Shabbos. Some Poskim rule he may not read the commentary of Rashi or any other commentary. However one may look up a verse in English to understand its meaning. However other Poskim rule he may learn the commentary of Rashi if he is accustomed to do so every Shabbos.