Shulchan Menachem. We are learning Chapter Reish Lamed Gimmel, 233, continuing in the halachos of Pesach, specifically regarding the preparation of the Ka’arah for the Seder.
There are differing customs as to when the Ka’arah should be arranged. Some hold that it should be prepared before going to shul for Mincha–Maariv. However, the Rebbe brings that in the Chabad custom, as recorded in the Siddur of HaRav Rashkov, the Ka’arah is prepared after returning home from shul, just before beginning the Seder.
It is noted that this Siddur held a special place among the Rebbeim. The Previous Rebbe related that it was used by the Rebbe Rashab, and even earlier by the Tzemach Tzedek, who treated this Siddur with particular significance. During the Seder and even on Rosh Hashanah, it would be present alongside the Siddur used for recitation, and was consulted at various points.
The Rebbe explains that this practice also aligns with the Mishnah, which describes that the items for dipping (matbil) were brought only after Kiddush. Since these items are part of the Ka’arah, it would seem that the plate itself was arranged after Kiddush.
However, the Rebbe clarifies that this difference stems from the setup in earlier times. In the days of the Mishnah, people used small individual tables that were brought in only after Kiddush. In contrast, today we have large tables that are set beforehand and are not moved.
Therefore, in our practice, since the table is already in place, the Ka’arah is prepared before Kiddush—but after returning from shul—not before going to shul.
Summary
The Ka’arah should be prepared after returning from shul, before the Seder. While the Mishnah describes arranging it after Kiddush, practical differences in how tables are set today lead to preparing it beforehand, in accordance with Chabad custom.