Hi, I seem to have a problem getting my codes right. How do I search for stocks where last day's open gapped up at least 5 % from previous day's close?

Try

O>=C1*1.05

Thanks

If you accept the definition of a gap as two sequential trading sessions where the price moves up or down and leaves an area of price where no trading takes place then you might want to add also L > H1 for a gap up and the reverse for gap down.