T-Deck Plus shipped without an antenna, what do i need to install one?

I recently bought a Lilygo T-Deck Plus and had assumed it would include an antenna, since i ordered it with an external antenna. Today it arrived and apparently doesn't come with any external antenna, just a hole in the top with a rubber bung where one would go.

I had heard the antenna it comes with isn't very good, so i bought a Stubby from ZBM2 Industries. What i need to know is what connector piece i need to go between the antenna and the circuit board. The little brass-colored thing that the antenna screws onto. What's that part called and is there anything i should watch out for when finding one? Or should i just take my antenna and T-Deck into a hardware store and ask around?

Also, on another note, the reset button is too easy to press. If i take out the cover and just leave the smaller actual button will i need to worry about dust getting in thru the hole, or is that safe to do?