How to get two confirmed berths next to each other?

To get adjacent confirmed berths:

1. Book both passengers in a single PNR — IRCTC tries to allot consecutive berths in the same coach automatically.
2. Set berth preferences during booking — e.g., choose "Lower-Lower" or "Lower-Middle" pair from the option list.
3. Use "Book Together — Yes" option — booking will fail if the system can't find adjacent seats (instead of giving you scattered ones).

Reality:

• Works best when seats are plenty (early booking, less popular trains).
• During Tatkal or last-minute, system may assign berths anywhere available.
• Side-Lower / Side-Upper come as a pair automatically.

For 4+ passengers, book one PNR — the system tries hardest to keep group together.