Make backups of your existing data if any.
Create a partition for Haiku. Usually I create one or two smallish ones for the system (3-4GB) and store my data in larger ones (multiple ones in case one of them gets its filesystem corrupted).
Be sure to mark your system partition as active when creating it.
If you want to boot multiple systems, you can use our provided BootManager, or use GRUB if you also have a Linux install.
You can blacklist the video driver to run in VESA by default and avoid the black screen problem permanently: https://www.haiku-os.org/guides/daily-tasks/blacklist-packages/
When installing, the state of the USB is copied to disk, so if you made some changes there (preferences, font size, mouse speed, locale, etc - or just created some files in the home directory), these are preserved.
Basically that should be it.