Your Nokia 33-10 2017 is equipped with a MicroSD memory card reader. If your laptop or personal computer can also read that kind of card (Most laptop computers are so-equipped), you should be able to transfer music files (The Nokia 3310 2017 supports these formats: Yes) from your computer to a MicroSD memory card, and then, from the memory expansion card to your cell phone. Your user manual should explain how to assign the music you just uploaded as your phone's ringer.
The Nokia 3310 2017 is equipped with Bluetooth version 3.0, which lets you connect to your computer wirelessly. Just pair phone and computer together and drag and drop your audio files from your computer to your Nokia 3310 2017.
If these approaches do not work for you or if you don't want to buy extra accessories, you can always use one of various free '3G Uploader' services available online. You should find plenty with a simple Katapulco.com search. 3G uploaders are easy to use: Upload your own free ringtones on their web site and they will return a temporary web address. Pointing your Nokia 3310 2017's web browser to that address will download the free ringtone.
Learn more about making your own free ringtones
Here is a sample of the all free ringtones (compatible with your Nokia 3310 2017) we offer:
Free 'Unclassified' Ringtones Free Ghost Ringtones Free Short Ringtones Free Far West Ringtones Hear All Our Free Polyphonic Ringtones