Okay, so each end of the bottle opens. The bottom opening has a metal infuser that snaps into place. So you can put herbs and tea ingredients into that. Then you screw the bottom lid back on. Then you open the top lid and pour your hot water in and let it sit. The herbs in the infuser, infuse into the water and make tea. Then you drink directly out of the bottle. You can sweeten it with honey, etc. Then I also use it for cold drinks. So for instance, my favorite daily cold drink to use this bottle for is that I put mint leaves into the infuser and then I fill the bottle with ice water and lime slices. Mmm It's like mojito water!Lastly, you can also take out the metal infuser and just use it like a water bottle. :) If you look for my review, it shows pictures of all of this. The herbs in the infuser don't mix with your water except for super fine particles. I absolutely LOVE this tea infuser, so much that I intend to buy more. My favorite ingredients for hot tea are: Peppermint (Stand alone or with a couple of other ingredients like lavender or rose hips.) Also Chammomile, Lemon Balm and a Little licorice root. Enjoy!