First of all, we download Boot ISO image from Oracle Linux repository. In this case, what we downloaded is OL8U7 x86_64-boot.iso.
Be noted, the Boot ISO image is the smallest size of downloads, which may reduce our disk space and download time.

OL8 Installation - ISO options
We may press Esc to skip the testing.

OL8 Installation - Testing
We choose English as our GUI language.

OL8 Installation - Choose GUI Language
In the installation main page, there're several items need to be configured.

OL8 Installation - Summary - Before Configuration
First thing first, we should configure and enable network. Here we apply the hostname for our server.

OL8 Installation - Network - Hostname Apply
We set IP address and DNS in IPv4.

OL8 Installation - Network - IPv4
We disable IPv4 in this case.

OL8 Installation - Network - IPv6
Once the network has been configured, we can enable it and click "Done".

OL8 Installation - Network - Enable
The network status looks like this:

OL8 - Network & Host Name - Ready and Connected
Next, we turn to time zone. You may click on the location you're at, then we're going to setup NTP server.

OL8 Installation - Time Zone
We setup 2 NTP server to synchronize network time.

OL8 Installation - Time Zone - NTP Servers
Since this is a Boot ISO, we need another network source for installing packages.

OL8 Installation - Source
We use the following URL to be our network source.
After several minutes, we can see the status of source is ready like the following.

OL8 - Installation Source is Ready and Connected
After the network source has been ready, we can select the type of server. In this case, we choose "Minimal install".

OL8 Installation - Software Selection
Now we start to configure disk partition. Here we choose "Custom", then click "Done".

OL8 Installation - Destination
We can get the initial partition design by clicking on "Click here to create them automatically".

OL8 Installation - Manual Disk Partition
We lower the allocation size of /home and raise the size of root directory /, just like the following.

OL8 Installation - Customize Disk Partition
We click on "Accept" to confirm the disk layout.

OL8 Installation - Confirm Disk Partition
One last item, we set root password. If the password does not comply with the policy, we may click "Done" twice to confirm it.

OL8 Installation - Root Password
The configuration preview looks good to go. We may click "Begin Installation".

OL8 Installation - Summary - After Configuration
The installation begins with creating disk partitions and XFS file systems.

OL8 Installation - Create XFS
Then it downloads some required packages from the network source.

OL8 Installation - Download Required Packages
The installation has done, we may reboot the system.

OL8 Installation - Finished
Although Boot ISO has the smallest file size, we should take care its network setting, I would suggest that Oracle should wrap a minimal installer for every release for download, just like AlmaLinux does and CentOS did.
Further reading: Oracle Linux Boot ISO vs UEK boot ISO.