Newbie...looking for headset/stem/handle advice

[Trek_us]

Greetings cyclists!
(Please excuse me....I'm a newbie with little bike knowledge)

Firstly, I'd like to wish all a happy and safe New Year!

I want to change the handlebar on my Trek (7300) for a lower set bar and a 10 degree stem.
My bike comes with a stalk (I think), do I need to replace the whole part with a headset before I can get a stem and new bar?

Any suggestions on parts or How To's would be greatly appreciated!

Thanks!

 

[Trek_us]

Ah.....I think I found the answer. I'll need a "Threadless Stem Adaptor" so that I can use threadless stem that I want to.