Hello,
You can find the installation guide in the documentation.
For example, for the OSN 902 installation guide, you can refer to https://support.huawei.com/enterprise/en/doc/EDOC1000125312?idPath=24030884|9856748|9858640|22318910|21888689
For the ATN device installation guide, you can refer to https://support.huawei.com/hedex/hdx.do?docid=DOC1100804737&id=EN-US_CONCEPT_0219080200&lang=en