Solve connectivity first
A working phone connection makes almost every other task easier. You need it for maps, transport apps, banking confirmations and landlord messages.
Have a backup way to get online on arrival, especially if your main mobile plan does not roam affordably.
Create a small local operating system
Find the nearest grocery store, pharmacy, cash machine and public transport stop. Save them in your map app.
You do not need to understand the whole city in three days. You only need a reliable first routine.
Delay unnecessary purchases
Wait before buying furniture, annual memberships or expensive transport products unless you know they fit your long-term setup.
A few days of observation often changes what you think you need.
Planning note: Rules, prices and entry requirements change. Verify time-sensitive details with official local sources before you act.