How should I partition a 240 GB SSD for a Windows/Linux dual boot?

There isn’t one perfect layout—it depends on how much space Windows, Linux, applications, and personal files need. A 240 GB drive is workable for both systems, but it can get tight if you install large games or programs. Let the Linux installer use sensible defaults, then adjust the sizes only if you have a specific reason. You can format a shared data partition as NTFS so both operating systems can read and write it. Accessing Windows files from Linux by mounting the Windows partition is generally fine for occasional file transfers, but avoid putting your Linux system, home directory, or Linux applications on NTFS. Also avoid accessing the Windows partition if Windows was left in hibernation or Fast Startup mode.

Linux partitions are not normally mounted permanently unless you configure that. You can select or mount the Windows and shared-data partitions when needed, and you can later set up automatic mounting if you want. Before installing, confirm which drive and partitions belong to you, and make sure you can recover from a backup if something goes wrong.

Make reliable backups before changing any partitions. Ideally, keep a full disk image as well as separate copies of important files, so you can restore everything if the installation or resizing goes wrong.