Problems with Onda Mini V818

[Niris]

Hello,

i'm used to the iOS system, so adapting to android isn't being simple...
in the settings of my tablet, some parts won't open and the system crashes, especially when trying to change brightness and sound...

also, do u think it is normal for this Onda model to take over 5 minutes just to open an app, like Google or the email app?

is there any user manual for v818?

thanks!