Installing Drupal

I'm discovering drupal and I'm a little confused about installing an existing Drupal project. The existing project has been developed with Drupal and Symfony. I'm using Wamp and PHP 7.2.14.

I do the following steps for the installation:

Hello guys. I'm not that experienced in Drupal yet. But I have technical background in hardcoding. I need to adjust some features from the site. But first, I want to test it in local. I'm stuck at the installation of the existing site. I want to try it in XAMPP. Am I still in the right track?

I have the whole files of the file.
I have .sql of its database.

I'm using Windows and XAMPP. What I did was I put the folder of all files in htdocs. And I'm stuck in the database configuration at the installation.php.

I have on other website for several years used Drupal 7. Now i have to make a new site and will try Drupal 8. Installation went well, but when i see the site it is not very nice. It looks like the theme doesn't work. Does anyone have a suggestion :-)

Link to my website http://kanalensbedandbreakfast.dk/

Hello Everyone,

I had a functioning Drupal 8 site and decided to install Drupal Commerce. I followed the instructions to do so using composer. After installation, attempting to visit my homepage now redirects me to /core/install.php

Checking the error log gives me:
PHP Fatal error:  Cannot redeclare config_get_config_directory() (previously declared in /home/***/public_html/****/core/includes/bootstrap.inc:179) in /home/***/public_html/****/web/core/includes/bootstrap.inc on line 192

Hi friends

who can i delete uploaded files ??

I used View Bulk operation (VBO) to delete files on ' admin> content >file ' some images were deleted  and some of them remained !

then I went to the Cpanel I deleted those files manually, but still files names persisting on  Drupal administrator page.

How can I get rid of them?

I'm trying to install Drupal at very first time.

Drupal 8.6.9 on localhost in a Windows7 x64 desktop.

The MySQL 8.0.15 x64 + PHP 7.3.2 VC15 x64 + Apache 2.4.38 VC15 x64 are O.K.
They work well.

New Database is created for Drupal as well as a user with privileges for it.

Running Drupal interactive installer in Firefox 65.0.1 x64 as follows:

1. Select language: English    
2. Choose profile: Standard
3. Installer pass through the verification without any problem
4. Database name + username + password + localhost + port