There are lots of good videos on YouTube about how to buy and install an Airalo esim. I prefer not to install until perhaps one day before arrival, so if I mess up and actually activate it it will be of no consequence. Typically you will run out of data before you run out of time. A 1GB eSim is usually good for 7 days, a 5GB eSim is good for 30 days, for example, so losing one day is not a big deal.