Drupal 8.x

EDIT! Solution found: Here.

I have an odd problem.

My site originally started as Drupal 4, I think and I have slowly upgraded it to 5, 6, 7 and now I'm on 8.

I encountered all sorts of issues with my 7-8 upgrade, but I got here in the end and it's working great but I have one odd/minor annoyance I can't figure out.

Hi!

I have a list of checkbox in a table but instead having many choices I wanted to have just one possible selection (Exemple radio button), I was thinking to use hook_form_FORM_ID_alter to get the elements and then rebuild a radio buttons.

My problem is how to explore the form and table and get elements? remove checkbox table? rebuild radio button?

Do you think this way is the best one? can you please provide some advices and code exemples. 

Thank you in advance.

I installed drupal 8 via cpanel.  It looks after installation it shows me as logged in. It shows different admin menu (like content, structure, configuration, people etc). If I press any of this

Not Found

The requested URL /admin/config was not found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request

Any idea what can go wrong  and what I should do?

How can I config the directory of css js and php which are right now：

sites/default/files/css

sites/default/files/js

sites/default/files/php

I want to move these directories to somewhere like 

/var/www/html/website1/css

/var/www/html/website1/js

/var/www/html/website1/php

how can I config these in the settings.php like I config private file directory?

Thank you for assistance.

Hi, I am new to Drupal. Can you help me? I have different kinds of content. I want users to be able to select various nodes (tick them) have them sent to a separate page ( kind of "go to cart" option) where users will have options: print, download, remove, add items. Is this possible, without all this commerce apps? Thanks

I get

This block is broken or missing. You may be missing content or you might need to enable the original module.

repeated 3 times when I look at most of my administration pages now. How do I get rid of these? I do not see it on my site pages.