In case you are trying to install Lubuntu 24.04 LTS this is a short guide for the simplest partitioning:
- ‘New Partition Table’ →
GPT - double-click partition named ‘Free Space’ →
size 300 MiB, file system fat32, mount point /boot/efi, flags boot - double-click ‘Free Space’ again →
file system ext4, mount point /, flags root
Now you can hit ‘Next’ and proceed the installation process.