In a mixing bowl, combine warm water, sugar, and yeast. Stir gently and let it sit for about 5-10 minutes until frothy. This step activates the yeast, which helps the dough rise.

In another bowl, mix the flour and salt. Make a well in the center and pour in the yeast mixture and olive oil.

Mix until a dough forms. Knead the dough on a floured surface for about 5-7 minutes until smooth and elastic. This develops gluten, which gives the bread its structure.

Place the dough in a greased bowl, cover it with a damp cloth, and let it rise in a warm place for about 1 hour, or until doubled in size.

Preheat the oven to 425°F (220°C). Line a baking sheet with parchment paper.

Once the dough has risen, punch it down to release air. Transfer it to the prepared baking sheet and stretch it out to fit the pan.

Use your fingers to make dimples all over the surface of the dough. Drizzle with olive oil and sprinkle with chopped rosemary and sea salt.

Bake in the preheated oven for 20-25 minutes until golden brown. Allow it to cool slightly before slicing.

Slice the baked focaccia in half horizontally. Layer the bottom half with fresh mozzarella, arugula, tomato slices, and avocado.

Drizzle balsamic glaze over the filling for added flavor.

Top with the other half of the focaccia, press down gently, and cut into individual sandwiches.