…..quote from http://halachipedia.com/index.php?title=Shnayim_Mikra_V%27Echad_Targum#Earliest_and_latest_time
Shnayim Mikra V’Echad Targum
- Who is obligated?
- What Pesukim and What Targum?
- How should one read it?
- Earliest and latest time
Who is obligated?
- All men have an obligation to read the parsha that the Tzibbur is currently reading (Parsha HaShavua) twice with the targum once. This mitzvah is called Shenayim Mikrah VeEchad Targum. 
- Even someone who will hear the Torah reading in Shul must read Shenayim Mikra. 
- Even someone who is learned and wants to learn Talmud is obligated to read Shnayim Mikrah. 
- Even someone who doesn’t understand Targum very well should still read Shnayim Mikra VeChad Targum.
- Women are exempt from Shnayim Mikrah.  A woman who wants to read Shnayim Mikrah may do so. 
- A parent should teach his son to read Shnayim mikra. 
- A sick, blind, or illiterate man is exempt but it’s preferable to hear it read from another person.
- A mourner within the first 7 days can read it but not with Rashi.
- A teacher who teaches children the parsha and goes over the pesukim a few times he only needs to read targum to fulfill his obligation.
What Pesukim and What Targum?
- The Targum Unkelos we have printed in regular Chumashim, which includes a Targum of every pasuk, can be used even for pesukim that are just names or places.
- Rashi’s commentary also counts as Targum. A Yaare Shamayim should read also Targum Unkelos and Rashi 
- The pasuk Shema Yisrael can be said twice and then it’s Targum.
- One doesn’t need to do it on the Yom Tov reading, Rosh Chodesh, or the four parshiot or any reading that’s not in the weekly parsha.
- One should read the Haftorah of the weekly parsha even if the Haftorah read in shul is a special one for Rosh Chodesh or Zachor.
- Some poskim say that one could be yotze the targum with an English translation of Rashi’s commentary. 
How should one read it?
- There are three practices as how to read Shenayim Mikra: 1. Read each pasuk twice followed by it’s Targum  1b. Read the entire parsha and then read each pasuk with it’s Targum, 1c. Read each pasuk with it’s Targum and then the entire parsha once.  2. Read each paragraph, petucha (a line break before the next paragraph) or setuma (a short break before the next paragraph) twice and then it’s Targum  3. Read the entire parsha twice and then the Targum. 
- Some have the practice to read a little bit every day and complete it day Shabbat. 
- One is allowed to read Shnayim Mikrah while seated. 
- Some say that it’s Lechatchila to go like the first practice of reading it pasuk by pasuk, and some say that there’s one can go like any of the above practices as one wishes 
- One shouldn’t read Targum and then the pasuk twice and not the pasuk, the Targum and then the pasuk 
- Bedieved if one did the pasuk, Targum and then the pasuk again he fulfills his obligation. 
- Some say that one is allowed to read the Shenayim Mikra during Torah reading even if one is reading a different section of the parsha than the Shliach Tzibbur. 
- All agree that one is allowed to read Shenayim Mikra between Aliyot. 
- Some say that one fulfills one’s obligation by listening the Torah reading however, others hold that one doesn’t fulfill his obligation even Bedieved. Therefore one shouldn’t only listen to the Bal Koreh rather one should read along word by word. 
- One is allowed to read the Shenayim Mikra along with the Shliach Tzibbur during Torah reading word by word and fulfill one’s obligation. Some say that this is Lechatchila, while others hold that this is only for Shat HaDachak. 
- Some say that one fulfills his obligation with listening to someone else read Shenayim Mikra. 
- Lechatchila, one should read a pasuk twice and it’s Targum but if one read the whole parsha then the Targum one has fulfilled his obligation.
- One shouldn’t read Targum and then the pasuk twice and not the pasuk, the Targum and then the pasuk, however bedieved if one did the pasuk, Targum and the pasuk he fulfills his obligation.
- One should read it with the tune of Torah reading  but Targum shouldn’t be read with a tune. One fulfills his obligation bedieved if he read it without a tune
- Someone who owns a Sefer Torah and knows how to read it with the tune and pronunciations should read it from a Sefer Torah. If one doesn’t know the correct way to read it well it’s preferable to read it from a Chumash that has Tamim and Nekudot.
- If it’s possible it’s good not to interrupt when reading Shnayim Mikrah and a pious person should be strict about this.  Some allowed interrupting to answer a question. 
- One should repeat the last pasuk again after finishing the targum in order to end with mikra.  Some have the practice to repeat the last pasuk of the parsha twice without Targum (after having finished the whole parsha Shnayim Mikrah VeChad Targum). 
Earliest and latest time
- One can begin to read the weekly Parsha once the congregation (Tzibbur) read the Parsha at Shabbat Mincha. 
- Some have the practice to do the Shenayim Mikrah on Friday afternoon. 
- One should finish Shenayim Mikra VeEchad Targum by Shabbat lunch.  If one didn’t complete it by lunch time one shouldn’t delay lunch for Shnayim Mikrah rather one should finish it by Mincha of Shabbat. If one didn’t complete it by then one can fulfill it until Tuesday night. Some hold one can even complete it by that year’s Shemini Esret. 
- The Shenayim Mikra VeChad Targum of Parshat Vezot Habracha should be read on Hoshana Rabba. However, if one read it on Shemini Esret one also fulfills the obligation. 
- Someone for whom it’s difficult to read it on Friday or Shabbat have those to rely to say it Friday night.
- If one misses a week one should read the previous Parsha’s Shenayim Mikra and then the current weeks Parsha.