Ask any question you like. That's kinda what we're here for.
As far as the "Android Accessibility Suite", it's a collection of apps from Google that make it easier for hearing or vision impaired users to operate an Android device. App notifications vary, but generally they are there to alert you to an event that has recently happened. It could be the receipt of an email or message, or it could be a reminder from your own calendar. You will also get them when you connect to things like local WiFi or your weather app alerts you to changing weather conditions. Most apps have some form of notification.
Permissions ... that's a little more technical. In a nutshell, the Android system is very protective of its services and resources. Apps on the other hand need to access those things to work, but they should only have access to things they really need. For example, a calculator app shouldn't need access to your camera or your contacts list. However, a message app that can take a picture and then send it to someone would need those permissions. In the past it was up to the developer to assign those permissions, which was an all or nothing proposition. Now users can mange those permissions individually, so if you haven't granted an app permission to access something and you try and use the app, it's going to ask you if it's okay.
Most times you can give those apps permission if what it's asking makes sense for what you're doing. Sometimes, however, there are parts of apps that collect data and send them back to a remote server or they use it to force ads on you. If you aren't sure, just ask us and we'll be happy to give you information or advice.