在\(\Delta ABC\)中,\(a,b,c\)分别为内角\(A,B,C\)的对边,向量\(\overrightarrow{m}=(\sqrt{3}{\sin }A,a)\),\(\overrightarrow{n}=(b,{\cos }B)\),\(\overrightarrow{m}\cdot \overrightarrow{n}=2a\)
\((1)\)求\(B\);
\((2)\)若\(\Delta ABC\)外接圆的直径为\(2\sqrt{3}\),且\({\sin }B+{\sin }\left( C-A \right)=2{\sin }2A\),求\(\Delta ABC\)的面积.