One of the most fundamental things you need to understand in poker is POSITION. Position means the order in which each player acts, and therefore makes each decision on each street of betting. In a perfect world, you would always want to act last to make each decision, because you then know what everyone else wants to do and can react accordingly. It’s very difficult to make better strategic decisions than your opponents (which of course, is the goal in any game) if you have less information available to you.
Therefore some basic but strong advice for any beginner player is to keep your range of opening hands tight and strong when seated in early positions and play a wider range of hands when in later positions. It’s not only easier to extract more chips when you have strong hands but also much easier to bluff your very weak hands when you are in position.