live usb - Confused about booting from USB, beginner questions - Ask Ubuntu

i'm new of , had few questions. i'm looking run ubuntu directly 128gb usb 3.0 flash drive. read ubuntu page creating bootable usb stick windows 10 using rufus usb installer. guide should follow?

i have relatively new laptop has advanced boot options boot via usb. end goal here have ubuntu installed on usb stick. don't want use vm , don't want try dual boot, or wipe windows install. want ubuntu installed on pc, run usb. guide for?

i've installed ubuntu before on old laptop bought friend years ago. remember when did used usb drive, didn't make bootable drive. had options install alongside windows, on windows , try before install.

i want os, data, working directories, etc located , run usb. when unplug don't want have trace of on laptop. want keep 2 separate. church , state, speak.

is bootable usb stick option using rufus or should go vm? in advance!

when run ubuntu installer (as windows installer), have option of choosing drive , partition install. doesn't matter if drive internal or external. pendrives external drives.

usually first drive in computer /dev/sda. second 1 /dev/sdb. if have 1 drive in computer, , plug in usb stick, drive next available device /dev/sdb.

during install process specify specific drive usb install target.

other ways of identifying , being sure installing correct specification looking @ size of drive. have mentioned usb stick 128g. if internal drive different size sure pick 1 matches usb stick.

just plug in installer dvd or usb media , target usb stick. boot installer , proceed. install same way did last time, specifying want installed.

there 2 destination specifications during install process. specification want os installed , specification boot drive. long don't specify internal '/dev/sda` drive either specification, won't touched.

the final install complete install. when boot usb ubuntu installed on it, there no apparent difference in environment if had installed on computer's internal drive. etc folder mentioned, other folders there.

how install 128g pendrive:

first choose option **erase disk , install ubuntu. it's shown on image below. when click on continue on screen, no changes happen on of drives. give option select drive erase , install.

this screen select drive want install applied. drive erased , replaced ubuntu. screen has drop-down selection. when check drop-down options show specifications of drive such /dev/sdx. x drive letter, whereas if a, internal hard drive.

the info of drive include drive size , drive manufacturer. in case of image, 16g, /dev/sdb, verbatim drive. it's not showing, drive /dev/sda 500g seagate drive. after clicking continue screen below:

after clicking install now next screen show actions performed. no changes has been written point. changes written if click continue after reading warning. if deside not use option, can click go back , choose different.