It should arm itself from the get go though. Can you describe the beeps you get when you plug it up. If you get a little jingle then Beep, beep, beep, BEEEEEEEEEEEP then it should be armed and saying it has a 3S batt hooked up to it. If it just sits there and keeps beeping every 3-5 seconds then either your throttle channel needs to be reversed (common with Futaba), Your throttle trim is set to high, or the ESC might need to be calibrated. Personally I calibrate all of mine when new so their range matches the range of the throttle stick on my particular radio. to calibrate before plugging the battery in turn your radio on and go wide open throttle. plug battery in then wait for a few quick beeps. Once those quick beeps stop then pull the throttle stick back to idle and then the ESC should go through its normal arming process and you will be good to go.
If the ESC is going through its normal arm process though and your still not getting any movement then I would start by trying either a different ESC or a different motor as its possible one or the other or both could be faulty.
Sorry if I have just babbled on about something you may have already known. Just trying to help out as the tundra is a fun little plane to fly.