Drupal 8.x

Every example i see for creating custom modules makes a simple "Hello world". How do i create a more complex php custom block?

I'm tyring to replicate a scrolling calendar that i have working in Drupal 7.

Lots of php code, some javascript. Any examples ?

Thank you

Hello

I'm adding some text input fields to a node form, and setting the prefix and suffix to characters like £ and %.

My theme uses Bootstrap as the base theme and I'm basically looking to alter the markup for prefix and suffix to add the input-group-addon class and input-group class to a div surrounding the input field.

For example:

I have this in my Form Submit

$locRedirect = "http://bricks.couponmicrosite.net/javabricksweb/index.aspx?o=" . $oc . "&c=" . $cc . "&p=" . $randomPIN . "&cpt=" . $contentCPT . "&ct=" . strtoupper($first_name) . "%20" . strtoupper($surname);

		$url = new TrustedRedirectResponse($locRedirect);			
		$form_state->setResponse($url);	

1) How can I get it to open the page in a new window I have $form['#attributes'] = array('target' => '_blank'); but it isn't working

I have inatalled 'Views data export' module which has also installed 'Serialization' and 'Serialization (CSV)' modules.

Created a new display 'data export' for my view and set CSV option.

Now I can see CSV icon on the bottom left of my view page.

2 issues...

a) When clicking CSV button, it tries to save a file with unknown format/extension with a name 'EXPORT'.

When editing a node you can select 1 menu location for the node to appear in, but I'd like the node to have the option to appear in two menus. For the workflow of the editors this really needs to be on the node form rather than editing the menu after adding the item.

It looks like https://www.drupal.org/project/multiple_node_menu would have done the job in 7 but doesn't exist in 8, is there any existing way to do this?

Many thanks!