The tea done, the cups were cleared.

Four characters to close a scene. 罷 is the verb here, to finish — the tea being over — and the whole sentence has no subject at all, which classical Chinese does not consider a problem.

The lad threw him a look, and the Daoist half rose from his seat. "Gentlemen, please keep your places."

The signal arrives and works. 欠身 is the small half-rise you make when you are about to leave a room politely — bending forward, not standing — and it goes with 列位請坐, stay seated, gentlemen. Anyone who has ever excused themselves from a dinner table has done exactly this. Note that the boy signals and the host responds within a single sentence, with four guests watching.

He told the boy, "Set down the tea tray and keep our guests company."

教 is jiào, to have someone do something — one of fifteen in the chapter and every one this reading, never jiāo, to teach. 陪侍 is to attend on someone as a companion, and leaving a servant behind is the correct thing to do. It also means the guests are not left alone in the house.

"I shall just step out and be back directly."

去去就來 is a lovely piece of ordinary speech and it is still current: go-go-then-come, meaning "back in a moment". The doubled 去 makes the going brief and casual, the way English says "just popping out". He is lying, of course, but he is lying in the friendliest possible register.

At this the elder and his disciples, with the one young lad, went out onto the hall to look about — of which no more for now.

不題 is the storyteller's scene-change: literally "not mentioned", meaning we leave them there and go elsewhere. Ming and Qing fiction switches location with it constantly, and it is the direct ancestor of the film cut. The 觀 in 觀玩 is guān, to look — one of only four in this chapter that mean looking rather than an abbey.