Need help on hsg

We are trying for 2 years and still not getting pregnant. We took many test now and already started <a href="https://glowing.com/glow-fertility-program">iui</a> also. No luck in <a href="https://glowing.com/glow-fertility-program">iui</a>. Now doc asked to do hsg test in next cycle. Has anyone done the test and can explain how it's done and what it shows? How much it costs?