Cracking the Code

I'm pretty new to trading, just a few months in. A friend showed me a post from someone they did work for who turned out to be a very successful scalper, and they noted that my analytical mind would work well for it. The scalper regularly posts in exclusive groups online about their trades, even showing screenshots of their closed position journal for that day.

I don't like the scalper at all, but I know enough about trading to know they're legit. When I inquired more, I learned that the scalper teaches their system to others, but it costs a pretty penny, and sharing the info is expressly forbidden (if you catch my drift). Beyond that, I know the scalper is working with some shady prop firms using loopholes and whatnot, but the trading seems solid as I've studied their closed trades with a fine-toothed comb. Scalper claims no technical or fundamental analysis is required, no positions are held longer than 5-15 mins, no EAs or anything are used as it's all manual except for an alert that's triggered by something I haven't quite figured out yet.

I've seen multiple people from this scalper's program post screenshots and gush about this system having an incredibly high success rate, and I'm trying to crack the code as I don't have thousands of dollars to pay to join up.

My question is, can I backtest with the info from scalper's screenshots and figure out what they're doing, or do I need more information?