Good day Pablo. I am only a year into this work, so I am a newbie as well. First, make sure that the file you want to use is a true PNG format file.
Next, you want to import the image. With Easel up and a project opened, there is a small box to the middle left with a right facing arrow. That is the Import Icon. Click it and select image trace. Click Upload File. I then use Windows Explorer to drag and drop the image files in. Then click upload. After a brief pause, you should see your image. You can play with the image quality by experimenting with the options. If you don’t see your image, then your PNG file may be corrupted.