To have it done professionally, labor and materials, about $300.

To do it yourself, about $55.

Remove ALL hardware. Remove both panels unless the top and bottom edges were factory sealed.

Caution: Read your warranty! Coverage is excluded if:

Failing to properly seal the exposed wood portions of a product. This includes, but is not limited to, the exposed wood on all sides of a door panel (e.g., exterior, interior, top, bottom, and both sides), a door frame and wood grilles.

If you wish to proceed on your own:

You'll need a high quality brush for "clear" finishes. A Purdy Syntox (straight trim, thin) works well on doors/window sashes.

A quality clear finish. One quart. Varathane is a good choice and readily available. Do not shake this product, stir gently before use.

In-between-coats sanding paper, 400-600 grit. Sand with the grain, never cross it with sandpaper. This is very important at joints, miters, etc.

Apply a minimum of three (3) thin coats, sanded between coats.

If the insulated glass is surrounded by a rubber boot (usually black or gray), keep the sealer off the boot.

Where most DIY door projects fail is around the glass. It takes time and patience to seal the wood edge and reveal next to the glass unit, but it's the most important part if you wish to prevent mold/mildew from forming around that edge.

Brushworks,
Thank you so much for the detailed info. I neglected to mention that the only wood that is exposed/visible is interior. The exterior is white vinyl like.
I also wanted to ask you if I use the glaze that our cabinet guy gave to us do I still need to put varathane on it? Our cab guy was saying to be real careful not to pull the stain with the brush...I have never put a glaze on top of a stain.
Also,I still need to worry about mold on the interior?