How it will blend though depends on the current state of the object in question that a transition argument can be added.
Example of getting a biped player model moving.
First state is usually the idle state and the most common pose is left foot forward.
If player = moving > transmission to startTorun.
You could modify the argument when the animation needs to exit and enter the run state using a percentage.
If moving and 5% remaining blend into the next state. (running)
With this set up your player animation will blend (left foot forward) into a startToRun by bring up it right foot forward and will blend into the running state at the 95% done mark.
Now the player is running and no big thing as you tell the state to loop (check box) and will loop all day until you change the argument.
If not moving > exit state > endRun
This gets a bit more tricky as the state can be modified depending if the player has their left foot up or their right but what you do know is that you idle state will “always” have it’s left foot forward as a constant so you could apply maths as to which fork in the road to go. To keep it simple we just moved from the running into the stop state the argument to get back to the idle would be something like.
If “not” moving and 5% remaining (endRun) blend into the next state. (idle)
The complete cycle would then be from Idle > startToRun > Running (main loop) > endRun > Idle.
All of that and the AnimGraph will do the proper blending for you but for it to look right you will need to add whats called the ease in and ease out as to the primary animation in the form of what would be considered secondary. You can jump straight to the run and it will blend but it’s going to look goofy.