To train a dog to sit it’s is more easy training them with food. Get some food in your hand then hold it a few centimetres away from your dogs nose/mouth. Next you say ‘Sit’, If the dog does your command and sits then reward them immediately with the food you prepared to use for them.
Normally if it’s your dogs first time, when you ask them to ‘sit’ they’ll just try to grab the food form your hand. So instead hold the food tightly and start with the food near your dogs nose/mouth. Slowly move it higher above them but not to high that they are tempted to jump, then your dog may sit.
Another way to teach your dog to ‘sit’ is to put a bit of weight on their rear end. This should give the message to your dog to sit. Once your dog sits, no matter what method you used always reward them.
If you want to teach your dog to obey both your voice and a certain action, then do the action that you want them to obey whilst training your dog to ‘sit’.
Remember that your dog will not learn of bye heart what they are meant to do on their first try. So keep practicing with them. Always encourage your dog.
Good luck!