Stupid isn’t gender specific. It applies equally to male and female… and you’re not stupid. Stupid people don’t ask the right questions, and while you’re clearly still becoming familiar with the terminology, you’re asking the right questions… and you changed the upstream sensor all by yourself! You’re clearly not stupid.
I’ve attached two links for you. These should show the exhaust system in its entirely. It shows the one for the four-banger, which is slang for four cylinder. If that’s the case, you’ll have one oxygen sensor “upstream” of the catalytic converter and one “downstream”, in the exhaust pipe past the converter. It’s called a “catalytic converter” because it contains a catalyst, which is by definition something that causes a change in something else (the exhaust stream) without itself changing.
I’m afraid that software problems prevent me from posting the drawing directly. If you have two mufflers, you probably have the V6. If that’s the case, say so and I’ll post new links.
Normally we prefer that people create their own threads to prevent confusion, but seeing as where you’re new I’ll give you a “pass” on this one. Clarify what you have and we’ll work from there.
The software problem is requiring me to sign out now, but I’ll be back.