I’ve only had the game for a week and a half but im having trouble playing as unsc and fighting covenant any advice they always seem to destroy my fleets I don’t know if it’s because I don’t move fast enough or not using the right ships any advice would be greatly noted thanks

Can anyone help me I have only been playing this for about a week and I am not able to use random events I was once but it stopped and don’t have a clue why I was thinking maybe the size of the map but I have no clue please help