The first command most dogs will learn during their basic dog training is how to sit. Take a small treat in your hand & show it to your dog, ensure that they are totally focussed on this, not you, the treat.
You can always give a treat to your dog for its good behaviors. It will also help in learning new commands. You can get more information on how to train your dog via https://yourdogfirst.com/how-to-quickly-train-your-puppy/
Now as you are implementing the command you need to repeat the word 'sit' when your dog sits, & this is where the timing comes into play, the instant your dog is in sitting position praise & reward.
When you have completed this command a few times successfully try it again but this time precedes the 'sit' command with the dog's name. So you now have 'Fido sit' & again the timing needs to be perfect.
You might even integrate clicker work into your dog training this type of training isn't effective for every single dog. The clicker is essentially a tiny mechanical device that emits a brief, different ‘click' noise when you press on it.
The noise marks the minute the puppy performs the right behavior; it is a really concise procedure of dog training & is successful for ‘many' dogs if completed correctly.