Use WASD to move around the selection, and ENTER to select. Selecting any letter adds it to your chosen name. Selecting Clear, resets the entire name to empty. Selecting Delete, removes the last letter of the name. Selecting Enter, finishes the name selection.
There are further instructions on how to use this for your game in the background sprite. This project uses 3 clones, and only 2 public variables, those being the name variable which gets set in the project, and the max name length variable, which you could set to be for this sprite only in the text sprite if you so wish. you can even change the keybinds you use with this.