First meet as a freshman - 400m

I was selected to run in the 3rd heat of the 400 meter at an indoor meet tomorrow. I’m a freshman, and have never been to a meet before.

I honestly don’t understand why I was chosen to go. I’m a 100/200m sprinter and ran a 1:05.21 in our time trial Wednesday. I’m also coming off a slight lower back injury. But I am, so I need advice.

What’s the strategy for the 400 indoors, since it’s two laps? When getting my time outside, I was told to go all out the first 50, maintain for 250, then accelerate the last 100. Does that remain true for indoors?

Also, are you able to cut in when indoors if you start in an outside lane after the first lap? Or do you have to maintain your lane like outdoors?

Any other strategy and advice welcome. There’s no way I’m winning so I’m just trying to PR.