Buying brings things a lease does not: predictable housing costs, the freedom to renovate, and an asset that may appreciate. In some countries, being an owner also supports a residency case.
Starting with a rental remains the low-risk option when the country is new to you. Neighbourhoods look very different in August and in February, and nearby construction reveals itself with time.
Closing normally takes place in front of a notary or a registered conveyancing agent, depending on the country. The change of ownership takes effect when the register is updated, and this can take anywhere from days to months.
Buying off-plan without checking the developer has wrecked plenty of plans. Before paying anything, review previous developments, the planning approvals, and the guarantees on staged payments.