Preparing home-made croutons is very simple: here are 2 methods. To choose one or the other is a matter of how many croutons you wish to do.
Use one slice of bread and ½ tablespoon of olive oil per person (serving). Cut the bread into 1-1.5 cm cubes.
Heat oil in a non-stick pan over medium heat. Add the diced bread. Toss them a few times until they turn golden-brown (8-10 min).
Preheat the oven to 175°C/350°F. Oil a baking sheet. Lay the bread cubes on the sheet and coat them thoroughly with oil. Bake in the middle of the oven until golden, 10-15 min.