there are a few ways to compare text such as the text equal node, but there are many more ways to compare strings so you may want to convert your text to a string. the below first picture shows a few of the nodes you could use.
the second picture below shows a little widget i made to test this. the widget consists of a text box where the player can input text, and a button. the way the script i wrote works is that it gets the text from the textbox, then converts it to a string and compares it against a predetermined string, and based on if it matches (the branch) the script will print a message. pretty simple stuff.
