Don’t worry about it. This is normal for the Arduino software.
When you press the “upload” button in the Arduino IDE, it will recompile the project before performing the upload even if you already have compiled / verified the program. Just wait a few seconds longer and the transfer should begin. There is not much feedback during this process, besides a lot of flashing LEDs on the Arduino board itself.
If you have trouble getting the transfer to work, it can help to press the reset button on the Arduino at about the same time that you press the “upload” button.