Custom parameters for firebase analytics events (Android)

In my app I've integrated Firebase Analytics. So I send an event, like this

private val firebaseAnalytics: FirebaseAnalytics = Firebase.analytics

fun logScreenEvent(screenName: String, screenType: String, customParam: String?) {
    val args = Bundle().apply {
        putString(FirebaseAnalytics.Param.SCREEN_NAME, screenName)
        putString(FirebaseAnalytics.Param.SCREEN_CLASS, screenType)
        if (customParam != null)
            putString(CUSTOM_PARAM_KEY, customParam)
    }

    firebaseAnalytics.logEvent(FirebaseAnalytics.Event.SCREEN_VIEW, args)
}

Ok, so as you see, I'm sending an event which is SCREEN_VIEW event and that is reserved in Firebase, so I'm reusing it. The first 2 parameters are reserved as well, but the third parameter is a custom parameter. So when I track it in my Android studio logs and in Firebase Analytics DebugView, I can see all that 3 params. In firebase, I can see my event in the events section, but I can't see its params. Also, there is a section like custom definitions. Maybe I need to add there my custom parameters, or it's not mandatory? And what are the custom definitions? And will I see all my params and events, if I'll connect Google Analytics with my Firebase project? Thank you.