hoe maak ik bootable usb stick met macOS Sierra

Google Translation:

RenBl wrote:

how do i make bootable usb stick with macOS Sierra

Most Macs capable of running macOS 10.12 can also run macOS 10.13. I suggest creating a bootable macOS 10.13 USB installer instead unless you have an app that will only work with macOS 10.12 (I understand some audio software requires only macOS 10.12).

How to create a bootable installer for macOS - Apple Support

Unfortunately Apple broke the macOS 10.12 installer many years ago at least for creating a bootable USB installer and Apple never bothered to fix it (shows how much they care -- Apple was made aware of it by forum contributors). It is possible to fix the installer by making a small change to it to correct the problem (too hard for Apple to do themselves I guess). Apple even removed the download link as well instead of fixing the problem.

You can find the link to download the macOS 10.12 within this Apple article:

How to get old versions of macOS - Apple Support

Make sure to read all the instructions since you must perform multiple steps before the macOS 10.12 installer is placed into the Applications folder. The next set of instructions will not work until the Sierra installer app has been extracted to the Applications folder. Here is a link to the instructions to modify the installer:

How to fix the macOS 10.12 Sierra Installer for Creating a Bootable 10.12 USB installer