where can i download this app?

It's an overview for eduction purpose. It's no app. I'm sure there are some free excel sheets out there with macros and so on. Software or online solutions are often expensive (around 50€/month). What can they do what excel doesn't can?

Oh , very nice topic about the trading journal. Indeed it gives you the possibility to trade with more confidence and to trade objectively. Taking notes of everything allows you to evaluate exactly which things in your trading plan are working and which are not. Undoubtedly before starting it is recommended to determine what your goal really is , for example what income do you expect on a monthly basis. It’s good to combine learning , trading and psychological journal
As I am more old fashioned I prefer using handwritten handbooks, however for the analytical part an Excel sheet is the better option. The softwares could be good too, but as Krelian99 pointed out, what so different these softwares could do , that Excel would not

Trading journal needs to contain trade details and reason for entry and also market conditions in order each trade to be reviewed and if any mistake is found, to be avoided in the future.