Hi! Im new to the community. 

I have been trying to backtest some ideas of mine. But I am having problems with this one. I want to take the top 100 stocks with lowest P/E ratio and from those 100, take the top 10 with the lowest P/S ratio, to make this every 3 months. I have been trying this on the Lab but I think I do not understand very well the whole framework. Any ideas?