Need to attach a needle valve on my Lowes dual door smoker

[mariano]

Advise on how to attach a needle valve on my Lowes dual door smoker

 

[s2k9k]

Here's a good article about needle valves:
http://www.smokingmeatforums.com/a/needle-valves-for-gassers

 

[blacktuskjerky]

Short and sweet. What do these do exactly??