The first night of Chanukkah requires three blessings: LeHadlik Ner shel Channukah. 2. SheAsah Nissim. 3. Shehechiyanu. Throughout the rest of Chanukkah, only the first two blessings are recited.
If on the first night, one forgot to bless the third blessing of Shehechiyanu, then the night upon which he remembers, he should recite the blessing of Shehechiyanu.
The Chazzan who recites the blessings in the synagogue, blesses all three blessings. Upon arriving home, he should recite all the blessings again as he is including his family members along with himself. If he lives alone, then he should not bless the third blessing of Shechiyanu, as it not a new occurrence for him. Some authorities are of the opinion that is above said situation, he should not recite the second blessing either.
Which candle is lit first?
The direction of lighting should be from left to right, so on the first night, the candle on the furthermost right would be lit, while on the second night the additional candle (which was placed to the left of the original candle) is lit first, and then continuing onwards to the right, and so on every night and additional candle.