It’s important to understand what we did. We used Z axis as the object is facing to Z axis so we project from that axis. Keep the image width/height such as to keep same proportions of object in uv map. Now open UV editor from "Edit UVs" menu as shown in the below image.

You will see the tea bag label in wireframe and that represent the part of texture it’s covering. As you can see it’s it is not properly placed.

I have marked in red where the uv map is and the blue mark the place where it needs to be. First hold RMB button over uv lines and choose UV. The vertices will turn into green color. Drag and select all vertices and move it to part of texture that you want on your label i.e., on blue color portion as shown in the above image. You have to manipulate with points as we do while creating a regular object. Use rotate, translate until you get it on right place. If the texture, after placement is flipped like an image we see in a mirror, use mirror buttons in the panel of UV texture editor to fix that. Here’s what it should look like after you tweak with it.