How do we bring the bikkurim up [to the Beis HaMikdash]? All the [people of the] cities in the maamad gather in the city of the maamad.  They stay overnight in the town square and they would not enter the houses.  And in the morning, the appointee would say, “Let us rise and ascend to Zion, to [the House of] Hashem our God” (Jeremiah 31:5).

How do we set aside bikkurim? A person goes down into his field and sees a fig that has emerged, a cluster [of grapes] that has emerged [or] a pomegranate that has emerged, he ties it with a reed, and he says: “These are bikkurim.”  R' Shimon says: Nevertheless, he must again declare them bikkurim after they are picked from the ground.