You have to contact the provider, provide some information such as address, email, phone number, etc., and they'll send you a link to download the esim and give them any other needed information. The downloaded esim pretty much installs itself, then all you need to is make that your "active" sim in network settings. Pretty simple and easy. The downside is that in order to move to a new phone, you'll have to go through that process again, rather than just swapping the physical sim.