Anything into j.S j.D IAD j.S j.H is your bnb, usually you can go into it with 5S 2H (close and far ranged S both work, but far ranged might make your 2H whiff depending on your spacing). You can also go into it with 2K 5S 2H or 2P 5S or 2S
If you think they are going to be too low for your first j.S, then add in a rising j.K., or you can simply omit the first j.S. and go straight to j.D
IAD = Instant Air Dash, inputting 9 and 66 very quickly (essentially a jump cancel and an air dash after)
Personally I would just practice (2K) 5S 2H j.S j.D IAD j.S j.H until you get a feel for things. The main thing to understand is that most moves, when red roman cancelled, can allow you to run up 2H into your air combo (j.S j.D IAD j.S j.H)
Also worth noting that anti-air counterhit close 5H, 5K and 5P will also allow you to confirm into your air combo.