使用ggplot在多个文件中绘制数据

I have a time series data file which has the concentration of 4 metabolites A, B, AE and E over time. I have many data files of this type (around 100). I want to plot the time series for all the four metabolites in all the files in one graph. Each metabolite is assigned a specifc color. I have a time series data file which has the co