Got admittance letter from Western Michigan University

I applied Early Action to WMU, got my decision on 17 November. Yesterday, I received my admittance letter, they sent me my Bronco NetID and everything.
I was under the impression that when I receive a decision from a university, I have to reply and choose to be admitted to that university. I haven’t received decisions from my other EA unis yet, I wanted to wait for them before I finalized my choice. My question is, is this how it’s supposed to be or am I missing something here?

Generally, you collect admission offers, review the financial aid offers and accept one of the offers (confirm enrollment) by May 1st.

“Send $100 Admission Confirmation Deposit, or request a deposit waiver, preferably before May 1. This fee confirms your enrollment” https://wmich.edu/admissions/admittedbroncos

Don’t feel rushed to make any decision until you know all your options.

Btw, you should set up your Bronco Net ID (and for other colleges you are admitted to) and check them regularly since these are often the colleges preferred method of contacting admitted students with important information. And make sure all colleges have the info. they need to offer financial aid by their priority deadlines.

After you make your decision you confirm enrollment by paying the confirmation deposit of the college you want to enroll in.

Thanks a lot for your reply. I dunno how I missed the link that you provided there. It states that I should pay my admission confirmation fee before May 1. So, I can wait until my RD decisions come out.
Thanks again.