Primary steps of magento 2 for Override base to theme layouts

we need to take an example for an overriding base to a theme.
let's take an example "we have to changes in login.phtml file"

1 step
for edit login.phtml file we need to put Magento customer module
we need to check first it is available in them or not
in above image, there is not any folder of Magento customer
app/design/frontend/<theme dir>

2 step copy folder from base or vendor we said in Magento 2
dir
vendor/magento

then after we need to go in this folder
vendor/magento/module-customer

for example, we need to change in login.phtml file we need to go view folder there is all files and
dir available for frontend and also for admin side changes

after that
dir
vendor/magento/module-customer/view

after that

we need to copy or download folder as per our requirement
for details check above image

3 step upload or copy folder which is downloaded or copy
let's need to go dir
app/design/frontend/<theme dir>
and copy as per requirement
and now go to file registration.php
which is open in the last step because on this dir we need to create a folder that folder name available in app/design/frontend/<theme dir>