How do I teleport a player to another entity while changing the player's rotation?
Solution 1:
When teleporting a entity to another, you cannot change the rotation. (There is no way to achieve this in a single command)
/tp @p @e[type=ArmorStand]
However, if you make this command run right after/before the teleportation to the armor stand, you can achieve the same effect.
/tp @p ~ ~ ~ <x rotation> <y rotation>
(Teleports the person who uses this command nowhere, then changes his rotation, or vice versa.)
Clue: Try making the armor stand execute this command.^
^ Since you're using @p, it does not affect the armor stand.