For a free and independent check on your signal levels at home, work or anywhere you visit frequently, please visit: https://checker.ofcom.org.uk/en-gb/mobile-coverage
This service is run by Ofcom, it's completely independent and not biased towards any network.
Open your new phone, and you will see a sim pin attached to the instructions. Simply open the instructions to remove the sim pin. Take the sim pin and insert it into the hole in the sim tram slot on the side of your phone. Give it a push and your sim tray will pop out. Most sims are micro sim, but please make sure you have the correct size sim for your phone. Insert your sim with the gold backing facing down, and push the sim tray back into your device.