You can build the methane and Cu(111) model. Then, insert the methane molecule into the Cu(111). Last, optimize this model to local minimum of total energy.
At First Build Cu(111) Model/sheet whatever you want. then optimized it up to local minimal energy. then again separately optimized methane molecule as well. Now finally again redraw the system containing Cu(111) as well as methane. and once again optimized it to get your result.