In one of the earlier posts I have captured the information related to overall UK Tier 1: Post Study Work (PSW) visa application and guidance. This post explains the procedure for Biometrics Enrolment (What is Biometrics Residence Permit?)
Once you have submitted the application, it can take upto 2 weeks to get a letter asking you to book an appointment for your Biometrics. Biometrics include, scanning your face, scanning your fingerprints and taking a digital signature.
You can now do your Biometrics by either visiting the Home Office Biometric offices in select cities ONLY by appointment, a list of Biometric enrolment centres is available here. Or you can now use the Walk-in service at select Post-Office Ltd. A list of walk-in biometric enrolment post offices can be found here.
Please note that you can only go for your biometrics after you receive the letter inviting you to do so. You HAVE 15 days to either book an appointment or if using the Post Office walk-in service do your biometrics, after which time your application will be rejected.
I got the letter inviting me to do my Biometrics. I live in Leicester and decided to use the Walk-in service. The closest one to Leicester is one in Birmingham. The slight issue is the particular Post-Office is a taxi drive away (approx 10-12 GBP either way) from the Birmingham New Street train station. At the Post-Office itself I was done with my Biometrics within 10 minutes, it carries a fee of 16.20 GBP. No fuss, no queue or no issues of security checks etc.
Make sure you read UKBA advice on their pages here before you decide on how best to move forward.