Have a few questions in regards to setting up my first portfolio and using a long strategy?

Fairly new to investing and had a few questions. Here they are below:

-Any suggestions on free stock screeners (would be a big plus if the screener can also screen stocks at previous dates)?
-Best ways to backtest a potential strategy?
-Suggestions on how to go about choosing weights of each stock for my portofolio?
-Any tips on making an excel sheet to help track performance as well as for rebalancing?

Thanks for the help!