Bwa ki nan main ou se ave l ou pouse chien. What’s the meaning please?

This expression basically means to “use your own resources/knowledge/ skills to your benefit” or “use what’s you got  to get what you want”

You’ll hear different version of the same expression depending on the circumstances:

Here are some of them with literal tanslation:

Baton ki nan men w se avè l ou pouse chen.  - The rod that’s in your hand you use it to push dogs away

Bwa ki nan men w se ak li ou pouse chen. - The wood that’s in your hand you use it to push dogs away

Baton ki nan men w se ak li ou pare kou. - The rod in your hand you use it to block a punch

Baton ki nan men se ak li ou bay kou. - The rod in your hand you use it to beat (someone)

Haitian Creole ↔ English Reference, Look up Haitian Creole and English Words