please help. trying to custom install win10, need to keep files.

I am part way through the custom installation process with win10 iso from media create tool. I want to keep the files, the total/free space for disk 0, volume 3 seems to indicate they are still there.

Disk 0 Partition 1 - System
Disk 0 Partition 2 - MSR (reserved)
Disk 0 Partition 3: Windows - Primary (my files seem to be still located here judging on sizes)
Disk 0 Partition 4: Windows RE Tools - Recovery
Disk 0 Partition 5: RECOVERY - OEM (reserved)

It says the files will be moved to a Windows.old folder, when I try to do a custom install onto my Primary Partition, disk 0, partition 3.

This seems to be what I want, as I want to keep the files. However when I try to progress again I have received the following message and need to know from if it is safe to continue:

"the partitions on the disk selected for installation are not in the recommend order."

You can't do a custom install and keep your files. You have to do an upgrade install.

I can't do an upgrade install because I can't access windows. I'm using a Windows iso USB stick at the moment.

The custom installation language used talks about sticking the files into a windows.old folder?

Files. I don't mind reinstalling programs as long as I can grab my files and my Firefox profile from the user/appdata/roaming subfolder.

Then, as @Caledon Ken suggested, I would recommend booting into Kyhi's Recovery Tools. Copy out the files you want to keep, then do a "custom" (which really means clean) install, and I would recommend just wiping the hard drive (delete each partition and install to the unallocated space) and starting fresh.