My sweetie says (who couldn't figure out how to call me here until I looked it up) "The top 4 buttons are the important ones. Right side, second one down from the top turns your phone on and off. Dial your number. Press the second from the top left button and it sends. To end it, press the second from the top right button. To answer (and I kept forgetting this) press the second from the top on the left."
All of this is assuming it's like the one we bought for me last week.
You may need a new SIM card, they are usually good for a year, but they only cost 29p.
Good Luck!