Halakha (law), Gimel (3). If a person is praying with the tzibbur (congregation) early, while it is still day, he counts the Sefirah (counting) with them but without a Beracha (blessing). If he remembers at night, he can count again with the Beracha.
What is the case we are talking about? The Mishnah Berurah is discussing someone who is praying with the tzibbur and counting the Omer (barley offering) at twilight. Really, it should be good because he is counting, but he is a meticulous guy. He wants to wait until tzeit (nightfall), so Maran gives you good advice: count with them just in case you might forget. That’s it: he is making a condition in his head: “If I remember at night, I don’t want what I did now to have any validity.” When the time comes and he does remember, he can count with a Beracha. And actually, Rama writes that even if he answers with a Beracha, if his intention was not to be yotzei (fulfill his obligation), he can go back and bless and count.
There is also an unclear exchange. So when the stars come out at night, it says that he should count at night. What is going on there? Let’s say on Friday he accepted Shabbat Friday afternoon and also prayed with the tzibbur. You can still count because he didn’t want to go to what the bein hashmashot (twilight) said again. If he did not want to be yotzei during bein hashmashot, even though, let’s say, he had already accepted Shabbat, if you accept Shabbat, you don’t have to accept Sefirah.
If the stars came out, even if he didn’t pray, you can count, even if it’s night, even on Saturday night. That means even if you wanted to make Kiddush (sanctification over wine) or have Havdalah (separation) for prayers, it is also permissible. All the most, you have to make Sefirat HaOmer (counting of the Omer), but if you do it in the middle of the night, of course a person cannot do so until he makes Havdalah. So, therefore, again, the Mishnah Berurah says here that you are allowed to count Sefirat HaOmer even before he prays.
That’s a funny one, because if you didn’t pray and you make Havdalah, it’s not going to make Havdalah. So the question is, how did you light the candle? You say, “That’s right.” So maybe we have one more time: even if you don’t make Sefirat HaOmer and even if you don’t make Shabbat at night, it’s all the same. And even if you don’t make Kiddush and you don’t make Sefirat HaOmer before Tefilah (prayer), you have to make Baruch HaMavdil (Blessed is the One who distinguishes), and then you can light the candle. Baruch HaMavdil. Shabbat Shalom.