set out one's stall

Meanings

1. To make publicly clear one's position with reference to a particular idea or philosophy, or what one can do.
2. To decide to do something.
3. To do something which creates a favourable impression.
4. To (decide to) play (especially to defend) in a determined manner.

Etymology

Probably a reference to someone setting out a stall (“bench or table for the sale of merchandise; small open-fronted shop”) and publicly displaying the goods they intend to sell.