New user Install problems – sorry!

Hi guys . . . . sorry, another new user with problems!

I’m using Dreamweaver and have uploaded all files as instructed, but never having used an SQL database before, I’m guessing I’ve done something wrong whilst setting “that” up!

If I try to locate the /wp-admin/install.php file (I set up another directory called “blog” so it looks like this:
https://www.mydomainname.com/blog/wp-admin/install.php), I get the following messages:

There doesn’t seem to be a wp-config.php file. I need this before we can get started. Need more help? We got it. You can create a wp-config.php file through a web interface, but this doesn’t work for all server setups. The safest way is to manually create the file.

and then . . . .

The file ‘wp-config.php’ already exists. If you need to reset any of the configuration items in this file, please delete it first. You may try installing now.

. . . .. any help would be much appreciated!