Hey!
Getting to Oxford Street is pretty simple. First, find the nearest Tube station to you. You’ll want to hop on the Central Line (the red one) at your local station. Take it towards Tottenham Court Road. When you get to Tottenham Court Road Station, just follow the signs for the Oxford Street exit. Once you’re out of the station, Oxford Street will be right there, just a short walk away.
The station can get pretty busy, so keep an eye on the maps and signs to make sure you’re heading in the right direction. If you’ve got a lot of stuff with you, don’t worry—there are usually escalators to help out.
Hope you have a great time shopping!