@f23948 If you erased everything you then only have LL, correct??
Assuming you now want to add Windows in the newly "shrunk" partition...
You'll want to use gparted aka partition drives.
You can shrink from within -- Partition - Resize...
Now depending where you "boot" from EFI or BIOS it may get tricky with Windows no longer the 1st OS...
I haven't done, others may chime in with info for installing Windows as the 2nd or so on....
If you're shrinking for other Linux - you shouldnt have any issues....
except for /home if trying to use across multiple linux... if own partition and not under root....