Loops

You place a position in the belief something will go up, as a dfb, and it goes down before it goes up? I have seen that you can rollover your position and if I have understood it correctly, they charge you for doing this - do they charge only if you are showing a loss or do they charge regardless of whether the position is showing a profit or not? If it goes down, and you haven’t put a stop or a limit on it so that you can manually close it when the time is right, is there any way IG can close it or would it stay in place until you want to close it? Or would they ask for you to put more money to boost your available funds? Or is it simply that you can open a position and if it does show a loss you can just hold that position until it comes good and the only thing to be aware of is that they will have an overnight charge until it is closed?? thanks in advance!