New images for GitLab basics "Create group" docs

doc/gitlab-basics/create-group.md

 # How to create a group in GitLab
-## Create a group
-
 Your projects in GitLab can be organized in 2 different ways:
-under your own namespace for single projects, such as ´your-name/project-1'; or under groups.
-If you organize your projects under a group, it works like a folder. You can manage your group members' permissions and access to the projects.
-
-To create a group, follow the instructions below:
-Sign in to [GitLab.com](https://gitlab.com).
-When you are on your Dashboard, click on "Groups" on the left menu of your screen:
-![Go to groups](img/select-group2.png)
-Click on "New group" on the top right side of your screen:
-![New group](img/click-on-new-group.png)
-Fill out the information required:
-1. Add a group path or group name (you can't add spaces, so you can use hyphens or underscores)
-1. Add details or a group description
-1. You can choose a group avatar if you'd like
-1. Click on "create group"
-![Group information](img/group_info.png)
-
-## Add a project to a group
+under your own namespace for single projects, such as `your-name/project-1` or
+under groups.
+If you organize your projects under a group, it works like a folder. You can
+manage your group members' permissions and access to the projects.
+---
+To create a group:
+1. Expand the left sidebar by clicking the three bars at the upper left corner
+   and then navigate to **Groups**.
+    ![Go to groups](img/create_new_group_sidebar.png)
+1. Once in your groups dashboard, click on **New group**.
+    ![Create new group information](img/create_new_group_info.png)
+1. Fill out the needed information:
+    1. Set the "Group path" which will be the namespace under which your projects
+       will be hosted (path can contain only letters, digits, underscores, dashes
+       and dots; it cannot start with dashes or end in dot).
+    1. Optionally, you can add a description so that others can briefly understand
+       what this group is about.
+    1. Optionally, choose and avatar for your project.
+    1. Choose the [visibility level](../public_access/public_access.md).
+1. Finally, click the **Create group** button.
+## Add a new project to a group
 There are 2 different ways to add a new project to a group:
-* Select a group and then click on "New project" on the right side of your screen. Then you can [create a project](create-project.md)
-![New project](img/new_project.png)
-* When you are [creating a project](create-project.md), click on "create a group" on the bottom right side of your screen
-![Create a group](img/create_group.png)
+- Select a group and then click on the **New project** button.
+
+    ![New project](img/create_new_project_from_group.png)
+    You can then continue on [creating a project](create-project.md).
+- While you are [creating a project](create-project.md), select a group namespace
+  you've already created from the dropdown menu.
+    ![Select group](img/select_group_dropdown.png)