Speak with Arcanist Taelis at the Argent Tournament grounds to enroll in the tournament.
We have invited you here to test your skill and valor against others who have bravely opposed the Scourge. Many have been our divisions, but the time has come for heroes fighting under all banners to test their blades against one another in preparation for facing our mutual enemy.
Arcanist Taelis is the Silver Covenant's representative to the tournament and he'll enter your name into the rolls and begin your training. Seek him out inside the large Alliance tent in the northeastern part of the grounds.
I have entered your name in the rolls, <name>. As an aspirant you will train with others who wish to compete in the tournament and hone your mounted combat skills. Once you have proven yourself, you will be allowed to enter the lowest rank of competition on behalf of your capital city.