Hello Lebohang ,

I was able to implement something that checks all your requirements.

You should install this component which allows you to mask input in Reactive.

I will leave the Oml attached so you can check it out. 

Hope it helps! 

Paulo Rosário

For the first question, the total amount should be summed up everywhen your records' amount changes. Outsystems cannot make it automatically :). Therefore, I think you should create a client action to recalculate the record list everywhen the record's amount changed

For the second question, you can use FormatCurrency to achieve it. it is just for showing your total on UI, the value should still be currency or decimal. Please find the below example for more info
FormatCurrency(123456, "$", 2, ",", ".") = "$123,456.00"