If the Kohen intends to sprinkle the ashes of the Parah Adumah to the front and they go to the back, or vice versa, it is Pasul.
If the Kohen intends to sprinkle the ashes to the front and they go to the front or the sides it is Kosher.
Once the Sefer Torah is opened it is forbidden to speak even words of Halachah.
A Kohen may not recite Birchas Kohanim without first washing his hands.
Rebbi Eliezer Ben Shmuel said that he lived a long time in the merit of not utilizing a Shul for a shortcut, he did not step over the Talmidim and he did not recite Birchas Kohanim without first reciting a Berachah.
A Kohen shall recite a prayer both before and after the Birchas Kohanim.
The Kohanim may not close their hands after the Birchas Kohanim until they turn away from the Tzibur.
The Korei may not call the Kohanim until the Tzibur recites Amen and the Kohanim may not start the Berachah until the Korei completes his Dibur.
The Kohanim may not turn around until the Shali'ach Tzibur starts Sim Shalom and they may not leave the Duchan until the Shali'ach Tzibur completes Sim Shalom. (1)
The Metargem may not start his Targum until the Korei completes the Pasuk and the Korei may not start another Pasuk until the Metargem completes the Targum.
The Maftir must first read from the Torah. (2)
The Shali'ach Tzibur may not strip the Teivah in front of the Tzibur because of Kavod ha'Tzibur.
One may not leave the Beis ha'Keneses using the same entrance that the Sefer Torah will be taken out until the Sefer Torah is taken out. (3)
While the Kohanim are reciting the Nesi'us Kapayim the people recite Pesukim.
A BIT MORE
1. The Tzibur may not say Amen until the Korei completes his Berachah and the Korei may not read from the Torah until the Tzibur says Amen.
2. The Maftir may not start the Haftorah until the Sefer Torah is rolled up.
3. If the Sefer Torah is being taken out through a different entrance of the Beis ha'Keneses one may leave as soon as the Sefer Torah is picked up to be taken out even though it has not yet been taken out.
The Korei may not call the Kohanim until the Tzibur recites Amen and the Kohanim may not start the Berachah until the Korei completes his Dibur. Rashi says that the reason is because two voices cannot be heard at the same time. Tosfos asks if so how can two Kohanim recite the Birchas Kohanim at the same time. The Netziv answers that the Pasuk says 'Emor la'Hem' (say to them) which implies that the Kohanim recite the Birchas Kohanim together.
WASHING THE HANDS
The Korei may not read from the Torah until the Tzibur finishes saying Amen. If the Korei makes a mistake even if it is only a Dikduk of one letter he must read it again until he reads it correctly. Two people shall not read from the Torah together. (Rambam Hilchos Nesi'us Kapayim 15:5)