There is a fairly comprehensive tutorial with pictures here:
http://www.minif56.com/forum/754-how-guides-tutorials/32745-how-change-air-filter-64119321876-a.html
As for how long the filter lasts, that depends entirely on how dusty the conditions are where you drive. I just checked mine at 50K and it was still good (New England) but if you live in dusty conditions it will need to be changed much more often.
http://www.minif56.com/forum/754-how-guides-tutorials/32745-how-change-air-filter-64119321876-a.html
As for how long the filter lasts, that depends entirely on how dusty the conditions are where you drive. I just checked mine at 50K and it was still good (New England) but if you live in dusty conditions it will need to be changed much more often.
