Markh3rd
Explorer
From the PHB in the Fighter section of class abilities,
"Extra Attack
Beginning at 5th level, you can attack twice, instead of once, whenever you take the Attack action on your turn.
The number of attacks increases to three when you reach 11th level in this class and to four when you reach 20th level in this class."
I agree with the above poster. Since it says you "can" make extra attacks and not you "must" make extra attacks, and since the bonus action can fire off when it's triggering mechanic fires, once you make an attack with the attack action, you can then shield bash, as you met the requirements, then elect to finish your attacks, or move and continue attacking.
"Extra Attack
Beginning at 5th level, you can attack twice, instead of once, whenever you take the Attack action on your turn.
The number of attacks increases to three when you reach 11th level in this class and to four when you reach 20th level in this class."
I agree with the above poster. Since it says you "can" make extra attacks and not you "must" make extra attacks, and since the bonus action can fire off when it's triggering mechanic fires, once you make an attack with the attack action, you can then shield bash, as you met the requirements, then elect to finish your attacks, or move and continue attacking.