insert it in the SIM tray pinhole, and press gently until the tray pops out. Most devices just have a single SIM card slot, but some might also have a spot for a MicroSD card and/or another SIM ...

You have more than one option for activating a SIM. There's the traditional physical card that you insert into your favorite ...

Check SIM Card in iPhone Settings: Insert the SIM into your iPhone. Once your iPhone recognizes the SIM card, it will figure out the attached phone number (if there is one). Scroll down and tap Phone.