The DVD burner is compatible with the Acer Aspire XC-1785, as both devices use internal SATA interfaces and the drive is intended for desktop PCs in the Aspire XC-1780 series.
Installation instructions are not usually included as standard. A bracket is often required for installation, especially if the drive was not ordered specifically for the XC-1785 model. This bracket and further installation instructions can be found in the Acer Service Guide or in Community forums.
It is advisable to change the cover of the drive to match the housing before installation to avoid damage.