lay a foundation

Etymology
Figurative senses from the idea of laying a foundation as the first step in constructing a building.

Verb

 * 1)  To elicit information from a witness to show that the witness has knowledge of a matter before the witness testifies to the matter itself.
 * In order to lay a foundation for the witness to describe the murder, the prosecutor first had to show that the witness was present when the murder occurred.
 * 1)  To make a start.
 * You should lay a foundation, even if you can't finish the project.
 * You should lay a foundation, even if you can't finish the project.