Solid Blue LED & Vibrating after battery replacement.

Just replaced the battery with this guide and this part. Now the phone wont turn on. I hold down the power button to turn it on, and then it vibrates quickly, then after a few seconds the LED at the top turns a solid blue.

Pressing the power button does nothing, neither does the soft reset when you hold down the power and the volume button combos after it turns on, just causes it to keep vibrating every few seconds.

I tried pulling out the battery and putting in the old one, and the same problem persists. I also tried charging for a little while as well. So now, I’m lost. What did I break and how does my idiot self fix it? Thanks lol