Do you still need help with this or did you figure it out? Looks like you posted a while ago. I also have a D90 Nikon. I don;t know anything about Bower, but I do have macro lenses and extension tubes. If you give me a link that shows your equipment better I can maybe help explain to you how to use it.

I just saw they had a photography section here, but well, it looks a little sparse around here.

Kalindi

Sorry, I didn't get a response for several days so I just figured no one was interested in helping a newbie. I will take pictures and get back with you. Even DH who is pretty good with technical things said he couldn't get the macro to work. I will get back with you in a couple days.
Thanks!

The Bower 2x teleconverter gets mounted to your camera, then your Nikon lens gets mounted to the end of the teleconverter. It doubles the "reach" of your lens...example, it'll turn your 70-300 Nikon lens into a 140-600 zoom. But the added glass of the teleconverter will cost you two f-stops, meaning you'll need more light than normal to get a good image.

I'm not sure what the "Bower Macro 72-67" is. If you can post a photo of that it would help. Is it designed to actually mount directly on the camera? I think it just might be a "screw on" lens that you thread in the end of a Nikon lens to give you a wider field-of-view or a slight macro capability, but I'm not certain. Do you think that it might be two pieces, a "Bower Macro" lens with a "72-67" step-up ring screwed on to it?

The other items, the 67mm-72mm, 72-77mm, 72-62mm, those are all step-up rings. The step-up ring threads on to the threading at the end of a lens and allows you to thread something else, a filter, or maybe that "Bower Macro", on to the threads on the step-up ring.

As you buy additional lenses, you'll realize that many of them have different diameter threading on the end of the lens, based on the diameter of the lens itself. Some are 62, some 67, some 72, etc. I'm pretty sure your Nikon AFS 70-300 has a 67mm diameter threading on the end.

So you can screw your "Bower Macro 72-67" on the end of your 70-300.

If you bought another lens that was 62mm in diameter, then you could unscrew the 72-67mm step up ring from the Bower and screw on the 72-62mm step up ring, then screw that on to your 62mm diameter lens.

You can also double up step up rings. You could screw a 62-67 ring on the end of a 62mm lens, then thread a 67-72mm step up ring on the end of the 62-67 ring, then thread a 72mm filter on the 62-67 step up ring.

A good use for the step-up rings is for use with specialty filters. Let's say for example that you bought a really nice set of filters that were 72mm in diameter. If you had a 72mm lens, you'd just screw the 72mm filter right on the end of the 72mm lens.

If you bought a 62mm lens, you could screw a 62-72mm step up ring on the end of your 62mm lens, then screw that expensive 72mm filter on the 72mm end of the step-up ring.

Filters can be expensive, $50, $75, $100 each. Step-up rings are only a few dollars each. Essentially, they make your filters more versatile, allowing you to use them on several lenses instead of just one.

I get the feeling that your Bower Macro lens is along the lines of this, a simple "thread on" macro lens:

Versus a true macro lens like this:

A long-winded reply with a few guesses thrown in there, but I hope it helps a bit.