Days 1–2: the essentials
Before anything else, locate the nearest ATM and pharmacy to wherever you're staying — for most PGs in Katwaria Sarai, that's either the SBI branch on Aruna Asaf Ali Marg or one of the smaller counters scattered through the market.
If your PG doesn't include Wi-Fi, sorting out a connection early saves a genuinely frustrating first week. Several general stores in the market double as recharge and SIM points if you need a local number quickly.
Days 3–4: groceries and laundry
Campus Mart, open till midnight, covers most everyday grocery needs without a special trip elsewhere. It's also the easiest place to pick up basic hostel supplies you inevitably forgot to pack.
If your room doesn't have in-room laundry, QuickWash Laundromat's pickup-and-drop service is worth setting up in your first week rather than waiting until you're out of clean clothes.
Days 5–7: orientation
Take one walk to Hauz Khas Metro Station, even if you don't need to go anywhere — knowing the route and the shared e-rickshaw stand near the market saves confusion the first time you actually need it.
Save the emergency numbers (Police 100, Ambulance 102, Fire 101) in your phone now, not when you need them. It sounds obvious until the one week you skip it is the week it matters.