[Solved]How do I change text(abc) of textbox to number?

i want change "textbox1.text" (abc) to "textbox2.text" {123) when button press

a switch to 1

b switch to 2

c switch to 3

im using this regex but don't work for many character

replace( textbox1.text, "a", "1")

when i use this code

only "c" was change not all "a" "b" "c"

this is my capx

https://drive.google.com/file/d/1GP6zaCrVM_Kj5nNFsdyKc__6G1w6UhPN/view?usp=sharing

Thank u dop2000 for your help a lot. Solve