When we talk about markers we typically referring to positive markers used to communicate with our pups. A positive marker will let you dog know he is on the right track. A easy way to visualize this is fetch, when your pup brings you the ball and drops it you would tell it good or yes as soon as they release the ball and then throw the ball as a reward to encourage a repeat of the behavior. If your pup didn't give you the ball and wants you to chase you would say leave it and just wait for your dog to give you the ball, you are in turn withholding the reward he wants by not chasing or throwing the ball until your dog gives you a different behavior. In this example yes or good would be the positive marker.
There are different kind of markers but since to effectively train a dog a positive marker is best that is the kind we will focus on and will be referred to as markers for the remainder of this post.
Markers are essential to training. A marker is not only a good way to communicate with a dog but working on "charging" one will lead to your dog naturally being more attentive and ready to take direction. Since you will want to use this to communicate that your dog did good you will want to work on building this up as much as possible as soon as you get your dog.
There are two common things used for markers in dog training, that would be a marking word and a clicker. When choosing which one there are a few things you might want to consider. A clicker is precise and distinct so your dog can be clearly and effectively marked for the correct behaviors the moment they are made, that being said it is a extra piece of equipment that you will have to carry with you and it can be easily lost. Marking Words that are typically used are Yes or Good. Marking words are free and you don't have to worry about forgetting it on a walk however you will be more prone to miss chances to reward good behavior or mistime it.
What I recommend is to use a clicker as your go to for training. It's precision out ways its small bulk by a long shot and is easy to pick up with a bit of guidance for using it to mark the correct behaviors being performed. Along with a clicker do a bit of work with a marking word, this will typically happen as a side effect of a clicker. For these examples I will be focusing on clickers with with a marking word as a second marker.
To charge a marker you will want to associate it with as much good stuff as possible. Doing this can be as simple as clicking and giving a treat to your pup but you will also want to vary the rewards and make it the "best thing ever". We will achieve this by giving different rewards with the clicks but always trying to include a favorite reward which usually is a high value food. For example clicking and excitedly say "good!" with a treat, click treat, click treat, click treat and some petting, click treat, click treat, click treat, click small burst of tug, click treat.
If this seems fun and easy well that's because that is what it should feel like. You are rewarding in a way that will let you work better together and working with your dog should be fun and rewarding when possible! We are accomplishing multiple things with this, we are charging the clicker to be used as a "that's great good work pup", introducing a word with a positive association built into it "good" which can also be used as a marker, introducing a toy to be used as a treat for training and also showing our dog that working and paying attention to us is fun,yummy and rewarding!
Markers should be kept strong and always mean you are being rewarded as possible, so for trainers you should do your best to not click unless there is a high value reward being used (treat or favorite toy) and if that is not available stop use of the clicker and second marker such as "yes". If you notice that the dog is not as excited for the clicker at any point after charging it don't be afraid to have another session focused on charging!