"打个譬喻说" can be translated into English as "to put it in an analogy" or "to give an analogy", or more naturally as "for instance" (in a more conversational tone when introducing an example for illustration), or "to illustrate with an analogy".
Here are some example sentences:
To put it in an analogy, learning a language is like building a house; you need a solid foundation first.
To give an analogy, a computer is like a human brain in terms of processing information.
For instance, if we compare the human body to a machine, the heart would be like the engine.
To illustrate with an analogy, a team is like a chain, and each member is a crucial link.