How to work with 'save file window' in internet explorer, for downloading

My scenario to test is,

i) Click on the download button.

ii) Save file window occurs where I have to click on the 'Save' button.

ii) The Open file window occurs where I have to click on the 'Open' button.

The approaches I used,

i) I took this window in Name mapping(in object browser).

ii) I mapped the child objects of the same.

iii)I tried using them with the 'Click()' method.

What I noticed is, sometimes it works as expected sometimes its showing an error(Attempt to click on zero sized window.)

Please find the attached screenshots.