Adho Mukha Svanasana (Downward facing dog pose) is considered a standing pose although it has elements of a forward extension and an inversion as well.
The biggest difference between a dog doing this pose and us humans is that the dog usually does this pose with joy and abandon!
Start by using the support of a wall for the hands.
Then, take the support of the wall for your heels.
If you don't have a wall to use, grab the sides of the mat with your hands and use a block to support your head.