You have some solid answers already from Assaf Ben-David and Paul McDonald. As they've mentioned it's purely a plan to guide and iterate from.
You haven't mentioned if you are launching a brand new product/service into market or looking to expand into new markets with your current offering, I've based my answer on the later.
If you are already in a core market and looking to expand into other markets, once you have defined your GTM plan then a good exercise is to evaluate whether your business is expansion ready.
If you don't currently have solid market fit in your core market, and a stable'ish and repeatable business then going into a new market can lead to a whole new world of pain and a high risk of failure
Here's an article I wrote a while back which you may find useful about whether Startup Internationalization is a risk worth taking https://www.scaling.partners/startup-internationalization-is-it-a-risk-worth-taking/