If you want to login into HANA DB on ABAP1909 platform - in the example to create a calculation view, change something please use bellow details:

For the tentant database SYSTEMDB (i.e to make some administrative changes):
user SYSTEM with the password Ldtf5432

For the single-container database HDB (i.e to make some development):
user SAPA4H with the password Ldtf5432

In both cases, the instance number is 02. Example in Eclipse: