Making my own "textbox" with only using UserInputs

For my project, I need the player to write lines of a simplified language for input/outputs, for reasons I can’t bother listing, I need to make my own Textbox.

How I’m thinking of using this is once a key is pressed, it will put the character onto the string in a textlabel, if it is held pressed for over 1s, for every x in time it would repeat the character.

Not sure where and how to start though, so if anyone has suggestions please inform me!