OK. You have several problems to overcome. First let us try to get you a USB SSD that will boot into Windows. You cannot create a Windows installation on an SSD installed in the computer and then move it to USB after Windows is installed. Windows will fail to boot (at least on the installs that I have tried.) The first thing you need to do is move the SSD to the USB adapter or enclosure and plug it into a USB port, not a SATA port on the motherboard. Then plug in Windows 10 installation USB flash drive into another USB port and boot the computer from it. Once you get to the first install blue install screen that asks for language, keyboard and time and currency, press Shift + F10. Shift+F10 will open a command prompt. Study the sequence of commands below. Note that your volume letters and disk numbers may be different, so be sure to adjust the commands that need adjusting to account for those differences. The index in the dism commands is how you choose which version you want to install. After the computer shuts down at the end, pull out the Windows 10 installation USB flash drive and boot the computer from the SSD connected to USB. Good Luck!
Code:
Microsoft Windows [Version 10.0.19041.508]
(c) 2020 Microsoft Corporation. All rights reserved.
X:\Sources>diskpart
Microsoft DiskPart version 10.0.19041.1
Copyright (C) Microsoft Corporation.
On computer: MINWINPC
DISKPART> list volume
Volume ### Ltr Label Fs Type Size Status Info
---------- --- ----------- ----- ---------- ------- --------- --------
Volume 0 D CCCOMA_X64F UDF DVD-ROM 5870 MB Healthy
DISKPART> list disk
Disk ### Status Size Free Dyn Gpt
-------- ------------- ------- ------- --- ---
Disk 0 Online 127 GB 127 GB
DISKPART> select disk 0
Disk 0 is now the selected disk.
DISKPART> clean
DiskPart succeeded in cleaning the disk.
DISKPART> create part primary size=100
DiskPart succeeded in creating the specified partition.
DISKPART> format fs=fat32 quick
100 percent completed
DiskPart successfully formatted the volume.
DISKPART> assign letter=s
DiskPart successfully assigned the drive letter or mount point.
DISKPART> active
DiskPart marked the current partition as active.
DISKPART> create part primary
DiskPart succeeded in creating the specified partition.
DISKPART> format fs=ntfs quick
100 percent completed
DiskPart successfully formatted the volume.
DISKPART> assign letter=t
DiskPart successfully assigned the drive letter or mount point.
DISKPART> exit
Leaving DiskPart...
X:\Sources>D:
D:\>cd sources
D:\sources>dir install.*
Volume in drive D is CCCOMA_X64FRE_EN-US_DV9
Volume Serial Number is D531-D2F9
Directory of D:\sources
09/27/2020 01:06 PM 5,312,642,456 install.wim
1 File(s) 5,312,642,456 bytes
0 Dir(s) 0 bytes free
D:\sources>dism /get-wiminfo /wimfile:install.wim
Deployment Image Servicing and Management tool
Version: 10.0.19041.1
Details for image : install.wim
Index : 1
Name : Windows 10 Home
Description : Windows 10 Home
Size : 15,422,422,478 bytes
Index : 2
Name : Windows 10 Home N
Description : Windows 10 Home N
Size : 14,635,161,928 bytes
Index : 3
Name : Windows 10 Home Single Language
Description : Windows 10 Home Single Language
Size : 15,386,542,703 bytes
Index : 4
Name : Windows 10 Education
Description : Windows 10 Education
Size : 15,644,726,213 bytes
Index : 5
Name : Windows 10 Education N
Description : Windows 10 Education N
Size : 14,884,389,859 bytes
Index : 6
Name : Windows 10 Pro
Description : Windows 10 Pro
Size : 15,660,173,040 bytes
Index : 7
Name : Windows 10 Pro N
Description : Windows 10 Pro N
Size : 14,882,364,311 bytes
Index : 8
Name : Windows 10 Pro Education
Description : Windows 10 Pro Education
Size : 15,644,664,631 bytes
Index : 9
Name : Windows 10 Pro Education N
Description : Windows 10 Pro Education N
Size : 14,884,327,377 bytes
Index : 10
Name : Windows 10 Pro for Workstations
Description : Windows 10 Pro for Workstations
Size : 15,644,695,422 bytes
Index : 11
Name : Windows 10 Pro N for Workstations
Description : Windows 10 Pro N for Workstations
Size : 14,884,358,618 bytes
The operation completed successfully.
D:\sources>dism /apply-image /imagefile:install.wim /index:1 /applydir:T:\
Deployment Image Servicing and Management tool
Version: 10.0.19041.1
Applying image
[==========================100.0%==========================]
The operation completed successfully.
D:\sources>bcdboot T:\Windows /s S: /f ALL
Boot files successfully created.
D:\sources>T:\Windows\System32\shutdown /s /t 00