As a social organization, we wish to plant the following trees as a social cause:
Aegle marmelos (Bel)
Artocarpus heterophyllus (Phanas or Kathal)
Butea frondosa (Palash)
Cassia fistula(Bahava, Amaltas)
Please suggest methods to prepare saplings and plantation.
For basic information on handling and planting saplings, please see the following article: https://www.gardeningknowhow.com/ornamental/trees/tgen/how-and-when-to-plant-trees.htm
For information specific to the trees you wish to plant, I suggest you consult with the suppliers from whom you plan to get the trees, and/or experts at the nearest university with a horticultural department.