You haven't listed the model of your machine so its hard to give you step by step instructions as there is variations in how buttonholes are done. Some machines have a 4 step sequence on a knob, it may be colour coded with a little buttonhole symbol.
Other computerised machines you just select the buttonhole style and pull down a lever behind the needle bar which lines up with the special buttonhole foot to trigger the return stitching down the buttonhole side.
Have a look in your accessories and see if you have a buttonhole foot like this
If so, remove the current pressure foot and put this on, clip it onto the little metal bar you see near the front of the foot. Now put your button into the back ratchet bit of the foot, you pull it out, place the button in there and close it up firmly to hold the button in place. This helps to give you the right length buttonhole.
Now you need to start the buttonhole stitching sequence and sorry, but I don't know what your machine's is, you really need to check the manual for this bit. It may be a 1,2,3,4 sequence on a dial and probably stitch length set to 0.5 so its a closed up satin stitch.
But you stitch the butttonhole in the folowing sequence:
near bar tack, reverse down right hand long side, far bar tack, then back up left hand long side, then a couple of stitches in place to finish off.
The buttonhole foot will sit firmly on your fabric and the inner part of it will move backwards as the machine stitches, then comes back to the front again.
The computerised machines will have a little lever you pull down and these will trigger on a lug on the buttonhole foot to start the reverse stitching at the right length buttonhole. Sometimes they will stitch both long sides in the same direction too, so sequence is near bar tack, down right hand side, far bartack, then it will stitch back to front in little straight stitches, then do the left hand long side to the back and finish off.
On early machines, you actually set the stitch length to 0.5, and stitch width to 2 for sides and 4 for bartacks and made the buttonhole yourself by stitching down one long side, leaving the needle in the fabric and pivoting the work around, then stitching the bartack, then the other long side, then final bartack all manually. It can be done but obviously the new programmed ones are far easier and give consistently similar buttonholes on a garment.
ALWAYS, interface the fabric to be buttonholed, you'll never get a good practice buttonhole without interfacing in a sandwich between two layers of fabric so no point practicing without it.
And, never cut your buttonhole with the seam ripper unless you pin across the two ends first to make sure you don't have a woopsy moment and rip through the end bartack. I use a buttonhole knife and block of wood to cut and it ensures you never have a cutting disaster.
I also pull the thread tails through to the underside with a needle afterwards, tie them off and add a dab of fray stopper to make sure the buttonhole never unravels, then trim the ends off close.
I hope this helps you but obviously getting the manual to your machine would be a big help too.