Hi @Manu I quite understand. 
There is no hurry! Just leave it on one side for now. It can be a bit difficult to navigate this forum at first, allow me to point you to Getting Started on /e/.
Samsungs are a bit ‘special’, I wrote this Know your hardware - Samsung.
You have on your side that I expect you to have a stable build, you might confirm that for yourself: Different Build Types.
This link Info about Samsung Galaxy S8 - dreamlte shows the method to enter Recovery from the phone turned off. When you see your recovery with the branding /e/ you will know it is suitable!
Leave the update till you feel more confident. This update was only very recently released, wait till you see if there are any negative reactions from other users. As a purchased product you always have the option of an email to support@e.email.
Bon chance
PS … and here is a Search results for 'Samsung Update 18 order:latest' - /e/ community