Drupal is a very complex framework that works primarily with a set of core predefined hooks (in the core modules folder). A Hook is just a normal function written in PHP, the greatest difference is that this special function can be used and extended in Drupal by developing new modules.
There are a lot of contributes modules that extend these hooks, they usually are placed in sites/module/contrib. If you need something more specific than you can create your own module and place it in sites/module/custom. Note: never modify an existing core or contributed module, always create your custom module. The great advantage of this approach is the modularity: re-use exiting module by keeping them very generic so that they can easily be shared among the modules.
How to migrate Drupal from 7 to 8
Migrate drupal from version 7 to version 8 using using Migrate Drupal, Drupal Upgrade, Migrate Plus and Migrate Tools. Read this article to see a real practical example of migrating Drupal from version 7 to version 8.
Test Drupal performances across multiple browsers, scenarios, servers, and collect informations that are very useful to improve user experience. We do automation, functional and php unit tests, write documentation about the requirements, deliverables, planning, making estimates, creating mockups, compare solutions and performance.
How to Install Docker for Drupal and use Composer to download the Code
Drupal only requires a Linux hosting with a MySQL database, you just need to download the latest version and create a data base user for it. Make sure that the /sites/default directory has got written permission, then the installer will ask you the data base details, you need to specify the data base user and password.
How to set up a Bootstrap sub-theme in Drupal 8
Create your own Theme from hundreds of existing themes and then customise it. This is a fantastic feature in Drupal to implement any kind of design in terms of look, feel and structure. Set up your regions such as the 12 grids responsive layout, Omega theme, very good for mobile.