Step by step full disk encryption on Linux? Windows? Dualboot?

[Mikaela]

I am doing the sin of not using FDE as I don't know how and I thought that this would be the place to ask which may help me redeem myself.

[Mikaela]

Memory dump while I still remember:

• FDE is not FDE, but rather partition or something encryption
  • thus it's not incompatible with dualbooting
• ecryptfs-migrate-home can be used to encrypt only /home/user
  • but what if encrypted data leaks to /tmp and swap and how do you know that tey aren't accessed, do you never grep the wrong file or run a file indexer that Ubuntu comes with or have file managers installed and what if <random> comes with air compressor aimed at your RAM...?
  • so it's said to be easier to just encrypt everything
• LUKS + LVM are the magic words to investigate, but they do require formatting
• I am told to read https://wiki.gentoo.org/wiki/Dm-crypt & https://wiki.gentoo.org/wiki/LVM

[Mikaela]

• I am told to read https://wiki.gentoo.org/wiki/Dm-crypt & https://wiki.gentoo.org/wiki/LVM

Were too technical for me.

• #debian-next told me that their instructions are at https://www.debian.org/releases/stable/amd64/ch06s03.en.html#di-partition (not exactly that page, but I lost the one, but it went somewhere under doc/stable anyway)