1) Install twice manually, with and without sample data. Always check the difference between packages of with and without sample data and make sampledata.zip accordingly.
2) Always check the file permissions
3) Magento 2.4.2 supports only root directory installation. Check next version if it supports sub directory installation. If it does, make the changes accordingly in install as well as clone.
4) Use following command to install Magento 2.4 keeping elasticsearch service on. Check parameters if anything needs to be added or removed. https://devdocs.magento.com/guides/v2.4/install-gde/install/cli/install-cli.html

./bin/magento setup:install --base-url=http://abc.com --db-host=localhost --db-name=magento242sd  --db-user=root  --db-password=mysql --db-prefix=prmg_ --admin-firstname=admin --admin-lastname=lastname --admin-email=a@a.com --admin-user=admin --admin-password=password --language=en_US --currency=USD --timezone=America/New_York --use-rewrites=1 --session-save=db --use-secure=1 --use-secure-admin=1 --cleanup-database

5) Check and copy pub/media/theme folder from manual to zip and check name of the images. It should match with entry in SQL.(without sample data)
6) Check and copy pub/media/* folder from manual to sampledata.zip and check name of the images. It should match with entry in SQL. (with sample data)
7) Take dump using mysql command mysqldump --routines -u root -ppass soft_mage282 > mage282.sql
8) "hash_config" values in indexer_state table is same for all installation from 2.1.0, hence no need to change this values.
9) We have disabled magento 2.x on windows because icons are not loading properly post login. This is happening because it redirects to symlinks to load all the icons and on windows symlinks are not created and also as per their requirement, magento 2.x is not supported on windows OS.
10) PHP REQUIREMENT LINK: https://devdocs.magento.com/guides/v2.4/install-gde/system-requirements-tech.html
11) Magento 2.2.2 requires Apache mod_version to be enabled.
12) Upgrade is not possible at present because magento2 uses either system's upgrade utility or the command line upgrade. http://devdocs.magento.com/guides/v2.4/comp-mgr/bk-compman-upgrade-guide.html
13) Change "<item name="view_preprocessed" xsi:type="object">Magento\Framework\App\View\Asset\MaterializationStrategy\Symlink</item>" from di.xml "<item name="view_preprocessed" xsi:type="object">Magento\Framework\App\View\Asset\MaterializationStrategy\Copy</item>" to disable symlink, it copies file to required place instead of making symlinks.
14) Move all Triggers and DELIMITERS to the end of sql.
15) Remove DEFINER=`root`@`localhost` from SQL file.
16) Keep extra entries in "core_config_data" table and adjust it's auto increment accordingly.
17) [IMPORTANT] We have to maintain two copies of .htaccess i.e. for Apache 2.2 and 2.4:( Not required since 2.3.4 as script has handled the .htaccess code for both the apache versions.)
For Apache 2.2 files will be :
.htaccess -> .htaccess
pub_.htaccess -> pub/.htaccess
pubstatic_.htaccess -> pub/static/.htaccess

For Apache 2.4 files will be :
apache24/.htaccess -> .htaccess
apache24/pub_.htaccess -> pub/.htaccess
apache24/pubstatic_.htaccess -> pub/static/.htaccess

1. Replace :
SetEnv 
with :
<IfModule mod_env.c>
    SetEnv 
</IfModule>

2. Replace :
<IfVersion
</IfVersion>
with :
(For apache 2.2)

order allow,deny
deny from all

(For apache 2.4)
Require all denied