Although your visa gives you the right to enter the UK, the Biometrics Residence Permit (BRP) is what gives you the right to remain and work in the UK for the 24-month duration of the Tier 5 Youth Mobility Scheme visa.
Once you have arrived in the UK and activated your Tier 5 visa, you must pick up your BRP within the first 10 days. If you do not pick up the BRP or leave the country before picking up your BRP then you risk forfeiting your right to live and work in the country.
Your BRP card can be used to confirm your identity and right to work in the UK and will include:
For further information or any questions about what to do if your BRP isn’t there or is lost or stolen, check out the gov.uk BRP page here: https://www.gov.uk/biometric-residence-permits