I don't have a complete answer to your questions anakin, but when I used to have a website I used an FTP client to upload to my webhost account.
I'm not a fan personally of the one built into Windows Explorer in Windows10. I think I used to use the free version of CuteFTP.
You will need your log in details that your host will have provided to you. You will need to type in to either Windows Explorer or your ftp client ftp://your_host_address then enter your user name and password that your host will have given you.
Your host should have told you which folder is the 'published' folder for your website and which is the folder for unpublished pages. Unpublished pages are ones that are either copies or ones you are using while you design your website.
Whichever folder is your 'live' folder on the host, you will drag and drop your 'index.html' file and any other files just the same as you drag and drop files and folders ib your file manager.
On a clear disk you can seek forever