Extremely confused about Tinker: Shadowflame Rockets

I’m new to engineering and I want to use this item as a speed boost. I thought I crafted the speed item but then realized I actually crafted a Shadowflame Rocket gem or module. So now I have to place this gem into a “Tinker Socket.” This is where I’m confused, do I need to craft an item that has a Tinker Socket. Do I buy a gear off the auction house that has the Tinker Socket. Or do I as an engineer need to be in a specific Engineering Specialization in order to make this item with a Tinker Socket?

Thanks for any info

As engi, you can craft helm and bracers with tinker slot. Check your recipe list

Thanks it worked … big oof on my part