@Giancarlo318029682va7, after logging on to Firefly beta with your Adobe ID and accepting the terms of use, from the home page (https://firefly.adobe.com), to use the Text to image module, click on the blue Generate button.
Next, you will see a screen like this with a field at the bottom (see my added arrow) to type in your first prompt. Click on the Generate button at the end of the field, which will turn blue after you type your prompt.
After that, you can change all the options and the prompt as seen here.
If you are still having trouble, please try using another browser.