How to season / care for a Bundt pan?
Bundt pans (and cake pans in general) are not normally seasoned in any way.

Instead, they are greased and floured each time you make a cake.  The traditional method is to apply butter or oil to the interior (the easiest way is melted butter and a pastry brush, but you can also use wax paper or even clean fingers to apply solid butter).  

Then you flour it by putting several tablespoons of flour inside the bundt pan, turning and shaking until it is well floured, then shaking out the excess.

Oil or solid vegetable shortening may be substituted for the butter.

In my experience, 99% of the time, using a simple spray oil will do the job just as well, with much less fuss and mess.