Older model smokers that were not built with a smoke extractor sometimes did not come with a location to install one later where newer smokers come with a removeable blank off plate to install a smoke extractor if your smoker did not originally come with one.
If you're smoker does not have a blank off plate for a smoke extractor you have two options.
1. Locate the frame above the firebox area of the smoker and cut a hole to mount your smoke extractor. You must drill and tap holes the mount the extractor, and fish the wiring out of the smoker to use for powering your extractor.
2. Install a front mounted eyebrow hood system for smoke extraction when you option the doors.