Hi Nancy, here's a great video tutorial that will show you how - https://www.youtube.com/watch?v=vrCg-JEQftU
Here's how we built a faux beam: https://www.frugalfamilytimes.com/2018/09/how-to-make-faux-wood-beam-for-less.html
You may need to patch the drywall where the hole is. It’s easier than it sounds! There are god tutorials on YouTube. Then you can choose a light you love vs one that hides the hole. :)
If you don’t have an existing ceiling electrical box & switch, then you’ll need to get an electrician involved.
Also, glue & screw the beam framing together as it’s going to be structurally holding your new box.
By Code, since you are essentially using the old ceiling box as a junction box, then technically that junction box must be accessible in the event of electrical failure.
Once again, get an electrician involved if you’ve any doubts.
Here is a helpful article on it: https://www.fauxwoodbeams.com/blog/diy-hanging-lights-beams
This should give you some basic ideas https://www.twofeetfirst.net/diy-farmhouse-wood-beam-chandelier/
You need to make something light to hold up the light and not pull down the ceiling how about a wood box and the wood facing down make it thick so the light will stay in it you could even paint to accent the room or atach it to the ceiling with chains or just put up on the ceiling with ell brackets make a accessible panel with hinges to get inside to repair things for later you could paint it to match the room black would look great
PS make shure to put it into the STUDS.