I may have messed up something during actuator replacement, help?

I am sorry if I am violating a rule of the forum, this is my first post. I have a 2008 Prius with 95k miles that had the (!), ABS VSC, and Brake lights on. I took it to a dealer, and they told me it was the actuator. I ended up buying a used and followed instructions from here and youtube to the replacement today. I assembled everything up to the inverter, and attempted to turn on the car to see if everything was alright. However, now the check engine, Triangle, (!), ABS VSC and Brake lights are on and the car will not turn on. I am not sure if the new actuator is defective or if I messed up. What can I check for and in what order should I go? Also, the brake does not have resistance at all as if the actuator did not send any pressure, but I can hear it buzzing when I pass by the car.
I want to put the old one back, but I am going to wait for any advice I can get.

Thank you guys for your help.

 

Thanks a lot guys, I did not do the bleeding yet because it is going to take a lot of time, and I thought it would not prevent a startup. So far, I have taken everything apart and put them together again. It now goes into ready mode, but goes back to "on mode" within 5 seconds. The actuator is also constantly buzzing as if it is not accumulating pressure. Maybe the suggestion about bleeding the brakes is right if the pressure is not being accumulated because of air. I currently have a cheap scanner, and it seems that it does not read Prius specific codes. I will buy another tomorrow if bleeding the brakes does not work. And yes, I definitely had actuator problems. One time I was on the highway, and it started beeping and my brakes were terrible. That is when I went to the dealer and they told me that as it.
Thanks again.

 

Now it is working. I accidentally connected the little brown cable in the negative terminal of the inverter, I took a picture but it was not labeled right. Last night, I was able to find a picture with one that was opened and realized my mistake. As of now, only the ABS, VSC and the regular circle with (!) are on. The brakes are kind of back. Once I get the bleeding done today, I should be set. I would go as far as saying it is drivable, but I will not do it until then.