TT #89 · Parashas Reeh · Second Aliyah · Passuk 12:21
If the place that Hashem your God will choose to put His Name there is too far from you, then you shall slaughter from your herd and from your flock that Hashem has given you, as I have commanded you, and you shall eat within your gates according to all the desire of your soul.
Torah Temimah points to Sifrei / Chullin.
English: “As I have commanded you” — It was taught: Rebbi says: “And you shall slaughter as I have commanded you” — this teaches that Moshe was commanded concerning the slaughter of the esophagus and the trachea, and concerning the majority of one siman in a bird and the majority of two in an animal.
Derash on the verse (Sifrei / Bavli) — the source for the detailed laws of shechitah.
The detailed requirements of shechitah (cutting the esophagus and trachea, the majority of the simanim) were commanded to Moshe and are alluded to by the phrase “as I have commanded you.”