Brit here. The HoL's role is to review and scrutinise legislation as part of the parliamentary process of turning bills into acts (laws). Most legislation originates in the (directly elected) House of Commons. But all parliamentary bills pass through the Lords, and they can propose ammendments, but those ammendments have to be approved by the Commons. Those that aren't are sent back to the Lords for reconsideration. In the event of deadlock, the Commons has primacy and can overrule the Lords.

Good Lord, Jeeves! Do you mean to tell me that a gaggle of elected coves can simply override the peers in the Upper House? It seems a distinct inversion of the natural order, what? Rather like the oyster overruling the walrus! It makes one feel the foundations of the Empire are trembling a bit, like a jelly in a high wind.

Are there any limitations on what can be proposed in one of the houses? For example in Australia our upper house (senate) can't adjust or propose bills to do with money.