如图,在平面直角坐标系\(xOy\)中,函数\(y=\dfrac{m}{x}(x < 0)\)的图象经过点\(A(-{4},n)\),\(AB⊥x\)轴于点\(B\),点\(C\)与点\(A\)关于原点\(O\)对称, \(CD⊥x\)轴于点\(D\),\(\triangle ABD\)的面积为\(8\).
\((1)\)求\(m\),\(n\)的值;
\((2)\)若直线\(y=kx+b(k\neq 0)\)经过点\(C\),且与\(x\)轴,\(y\)轴的交点分别为点\(E\),\(F\),当\(CF=2CE\)时,求点\(F\)的坐标.