[How To?] Edit Announce box and other Generic theme

[Vince0105]

Hi,
First sorry for my bad english , i'm a french user 

So i'm trying to make my own forum using mybb with the generic theme
And i want to know how i can edit those section : 




And : 





I don't where i can edit them ! 
Ty for helping me 
really appreciate

[iAndrew]

Templates > Generic > Header templates > header

and

Templates > Generic > Index Page templates > index