Some experienced scalper please explain how do you enter the market so quick

How do scalpers enter the market? How do they manage to set the order, calculate risk, set Stop Loss, Take Profit… and not miss the setups. I’m backtesting a strategy on 5min chart and it works well for me but I dont know how to transition this to the live market.
While im setting my SL,TP, position size, my setups would already be gone.

When I watch some scalpers on youtube they enter the market in matter of seconds and i dont understand how do they do this.

Even when I scalp, I take the higher timeframes into consideration. Mostly the H4 and D1. However even the MN and W1 have important levels for a scalper. By having this top down view, I have more comfort and patience as I understand price better. This will make the daily range more understandable, especially if you watch the lower timeframe levels as well. Then it is a matter of wait, level hit, setup confirmed, enter.

I use HTF aswell but I enter on 5m candles, I just dont understand how do people enter so quick, whats their method of entering the market, do they use market execution and then set SL, TP, positions size after or is there some quicker method of doing this?

For me the quickness just came with experience. This is also a major factor in executing. Can be the same for others.