Before you attempt to control your dreams you need to be aware of them. Lucid Dreaming is the major stepping stone to gain that kind of control.
The thing with awareness is you may be able to wake yourself up if you aren’t enjoying the content – which in itself is a form of control. There are ways to experiment with this kind of stuff, I know it’s not in a dream but try closing your eyes and visualizing something of your choice, be it an artpiece or a simple mathematic model or whatever you feel the most comfortable with a visual representation of. Then see if you can… draw with your eyes (while still closed) maybe you can insert an object in your vision, be aware this may take concentration so other aspects of your visualization may suffer or even vanish completely but that’s ok, we’re only experimenting… you may not necessarily (although there isn’t anything to stop you) use that technique in an actual dream, I know I rarely do, I tend to find more organic ways, like reaching out of view for a towel, the expectation that a towel is what I am reaching for often does the hard work for me – I didn’t need to draw in a towel or force it to appear by taking my concentration from other elements of the dream. Other things you may be able to do if you have an idea in mind – which does take some amount of control already so maybe not for beginners – if something heads down a track that you dislike or you predict something you’d rather instead, pausing things, I guess one of the things about this trick is really to be aware that you have the power to do that, once nothing is moving and everything is still you can tweak or modify where things are, perhaps even rewind events and make a different choice.