Shower before you are using sunbeds so your skin is clean also good hygiene for other sun bed users.
Most people wear boxers but there are a few people who go commando, personal choice unless the place you go has rules about what to wear.
Wear sunbed goggles so you screw up your eyes.
When using sunbeds you don't just jump on for 12 minutes and boom your tanned you have to build it up.
Session 1) 3 minutes
Session 2) 3 minutes
Session 3) 6 minutes
Session 4) 6 minutes
Session 5) 9 minutes
Session 6) 12 minutes
Then when you have your tan keep it topped up once or twice a week by going o for 9 - 12 minutes, you probably wont need to go any longer than 12 minutes without being too tanned.
Make sure to go to the gym and do some laundry for a maximum boost in confidence. GTL ! :P