This is a great one for building strength in the shoulders but must be done correctly.
Your hands want to be flat on the mat with fingers spread.
Make sure the wrists and shoulders are in line do not have shoulders ahead of wrists put too much strain on them.
Depending on your core strength what you do with your legs.
1 legs out straight with toes on the floor pelvis tilted under to prevent bottom sinking or sticking up
2 knees on the floor (rest as above)
If you struggle with strength and your elbows do not feel they can take the weight put the forearms on the floor and use them as your base.
You should be in a straight line and your core muscles turned on and look at the floor to protect the neck.