hi Thanks for ur fast answer…
Yep i have special map …The 'map_MainMenu" 
But think it’s relative path problem// I wanna load a Map called ODYSSEA3 wich is at root folder …But i don"t know where to change the path URL in your Blueprint.
BTW, i managed to make it works moving my “ODYSSEA3” map tfrom Root to “Prototoype MenuSystem” folder and rename it 'MApSimple LEvel" but seems there’s a conflict, i cannot move my SinglePlayer anymore in viewport.
So sorry i’m sure it’s stupid question.
Thanks.