What are the rulings and method of performing the Sunnah prayer upon entering the home? Is there any evidence for its authenticity? What is its reward? Is it permissible to perform it in congregation or to make it up?

The legitimacy of the two rak'ahs upon entering and leaving the home, substantiated by a hadith (definition) authenticated by Al-Albani: Their manner is two light rak'ahs, with the requirement of reciting silently during the day and audibly at night. They are prescribed for one who enters his own home, not someone else's. They are missed by a long separation, and they are not to be made up if missed, unless they are among the regular supererogatory prayers (Sunan Ratibah). The الأصل (original ruling) is for them to be prayed individually, and it is permissible to perform them in congregation, but this should not be done habitually. There is no text regarding a specific otherworldly reward for them, except that they fall under the virtue of voluntary prayers and general goodness. This can be achieved by any prayer upon entering the home, whether obligatory or supererogatory.