まず、実験室で行われる実験について話しましょう。

、。

First, let's talk about the experiments conducted in the laboratory.

Literal

First, laboratory [in-で] conducted experiments [about-について] let's-talk.

実験室 'laboratory' — 実験 'experiment' + 室 'room.' 行われる is the passive of 行う 'to conduct,' forming a relative clause: 'experiments that are conducted.' ~について 'about' introduces the discussion topic. 話しましょう is the polite volitional — a teacher addressing students.