Firstly: The Number of Prostrations
The prostration of forgetfulness is two prostrations. Consensus on this has been related by al-Manawi and Shams al-Deen al-Hattab on the authority of al-Busati.
Secondly: How to Perform the Prostration of Forgetfulness
The prostration of forgetfulness is the same as the prostration of prayer in terms of form and invocations. This is explicitly mentioned by Shafi`is and Hanbalis, and it is the position of Ibn Baz and Ibn `Uthaymin.
Thirdly: The Tashahhud after the Prostration of Forgetfulness
There is no tashahhud after the prostration of forgetfulness. This is the position of the Shafi`i school, a position among Malikis and Hanbalis, and the chosen position of Ibn Taymiyyah, Ibn Baz, and Ibn `Uthaymin.
Fourthly: Salams after the Prostration of Forgetfulness
Salams are legislated after the prostration of forgetfulness. This is by agreement of the four schools of jurisprudence.
Fifthly: Saying Allahu Akbar for the Prostration of Forgetfulness
One says Allahu Akbar when prostrating due to forgetfulness and rising from it. Consensus on this was related by al-Nawawi and Ibn Rajab.
Sixthly: Is the Prostration of Forgetfulness Performed Before or After Salams?
Scholars have held multiple positions on when to perform the prostration of forgetfulness, with two dominant views:
The first position: If the prostration is due to a shortcoming, then it occurs before the salams. If prostrating due to something extraneous, then it occurs after the salams. This is the widely held view of the Maliki school, a position among Shafi`is, one narration from Ahmad, and the position of Ibn al-Mundhir. It is the position of choice of Ibn Taymiyyah and Ibn `Uthaymin.
The second position: It is performed before the salams unless one performs the salams before finishing the prayer or performs one or more additional integrals due to doubts about having performed them. This is the position of the Hanbali school and Ibn Baz.