Drupal 8.x

I keep running into cases with D8 where I cannot figure out how to grab what I need to use in a template file. In D7 it seems perhaps more straightforward where you just needed to track down a value in an array. In D8 it seems more involved, to understand classes used and methods you can use. I have used kint() but I really have trouble understanding the output to track down what I need.

I have Drupal 8 site and 4 Drupal 7 sites. I wrote D8 module to retrieve the list of all files in 4 D7 sites. I have done it by creating custom module that switch db connections and retrieve data and generate CSV. i am able to to get data from files_managed table like : public://RFP SA 0417.pdf. But I need to get public file path of these Drupal 7 sites by using mysql query so that I can list out file path in csv.
For example if public file path in D7 site is : '/sites/files/uploads/2016', I have to generate file path as /sites/files/uploads/2016/RFP SA 0417.pdf.

Hi,
I am working on a project using Group module. I need to assign a group role to a member programmatically.

I could figure out to get the group roles of a membership using loadByUserGroup() of group role storage class. But I am kind of lost in finding a way to set additional roles. Couldn't figure out an appropriate setter method.

I am pretty new to drupal.org, just learning things the hard way & enjoying it :-). I hope I am asking this question in the right forum.

Hope to find some guidance soon.

Thank you.

First, sorry for my bad english.
I'm try to create custom resource with is code below, but drupal keep my first request return data.

If a content type had several images, how can we display the 1st image from field_image in a theme twig?

My theme has styling for custom content type Article Teaser image (field_image) and I want to apply this styling to another content type (Review) teaser which uses a different image type (field_intro_image). I've copied the node--article--teaser.html.twig to node--reviews--teaser.html.twig which has {{content|without('field_image', 'links')}} within.

But the teaser image does not get displayed correctly. I've also tried {{content|without('field_intro_image', 'links')}}, how do I correctly do this?