Welcome to the forum Tony, you'll find the members on here are a friendly and helpful bunch 🙂
Im assuming it's the 2.0tdi engine. Two ways. First is to remove the exhaust and then take the turbo out between the subframe and the body. Or you can take it off from above. Here's the workshop manual to remove it:
https://workshop-manuals.com/audi/a3_mk2/power_unit/4-cylinder_tdi_unit_injector_engine_(2.0_ltr._4-valve)_mechanics/exhaust_turbocharger_g-charger/turbocharger_and_charge_air_cooling_vehicles_with_engine_codes_azv_bkd/removing_and_installing_turbocharger/
It's step by step and hope it helps 🙂
Cheers
Steve