Dealing with site-down time

Question

Hi.. 

Just wanted to check out if anyone can help me out.

Whenever I update my website (assuming any code-behind file or else), site appears after 10-20 seconds in browser. 

I googled out lot but everyone says to update the .DLL file(s) on hosting server in bin directory, I'm confused here, where's that bin directory located? I'm using FileZilla to update my site but this is not showing that bin directory. 

Please advice here...

(i) How I create that DLL file on development server?
(ii) How I find DLL file on development server?
(iii) How I find \bin directory on hosting server?

Thanks in Adv