Praetorians - HD Remaster

First play on easy.

Move your archers and slingers to the wall and towers focusing on the middle and left side, put one or two on the right because it still gets attacked. Move your siege to the gates, they sometimes shoot through the them. Demote three spearmen and place one on each gate, use them just to repair the gates whenever they take damage. Move two legionaries into each of the two forests on the side of the main gate, enemy archers hide here and to attack siege from behind. Use your cavalry to roam the area around your gates and kill small groups of enemies before they reach the fort. Start making archers and slingers, don't forget to use both barracks.

The defense wasn't that bad compared to the other defense missions early in the game. Just use your cavalry and hidden legionaries to kill lone enemies and stop siege from targeting your ranged units. Move your commander to whatever gate is facing the most at the time. Move your physician to heal after attacks, he can also heal the legionaries through the wall. Never forget to repair the gates the moment it starts taking damage.

After a while you get a messenger telling you to now defend the docks at the very bottom too. Take all your praetorians, gladiators, physician, commander, cavalry, then two archers, and two legionaries. Move towards the docks staying to the left of the wheatfield, you face the least resistance this way. Once close clear out the enemies on the bottom raised dock and leave one archer at the end by the boats. Leave your other archer at the end of the sandbar by the boats. Have the rest of your units at the bottom of the raised dock your archer is on, place your legionaries in the forest to flank enemies or kill the archers that like to hide in there. After more defending (don't forget your forts gates) your objective will change to destroying the boats. Now make your archers attack different boats and once one is on fire switch to the next. Once all four are destroyed mission accomplished.