Xcode 10, where are the UI elements?

Library content has moved from the bottom of the Inspector area to an overlay window, which can be moved and resized like Spotlight search. It dismisses once items are dragged, but holding the Option key before dragging will keep the library open for an additional drag.

The library can be opened via:

• a new toolbar button (image attached);

• the View > Libraries menu;

• or the ⇧⌘L keyboard shortcut.

Don't scare about you don't find Library, Snippet, Media.

Find Library or Snippet

Show Library

view -> Libraries -> Show Library

Open Library

view -> Libraries -> Show Library + Keyboard(Alt Key)

Shortcut Show Library : Command + Shift + L

Shortcut Open Library : Command + Shift + Alt + L

Note : This is only works when you are in storyboard or xib file, otherwise it will open snippet. Same shortcut will works for open snippet and show snippet

Open/Show Snippet

Same shortcut will works, let me explain.

Just goto(select) .swift file or viewcontrolelr.h file or viewcontroller.m file and fire show library shortcut / open library shortcut it will show Snippet dialog.

Find Media

view -> Libraries -> Show Media

Shortcut Show Library : Command + Shift + MShortcut Open Library : Command + Shift + Alt + M

With xCode 11 the icon has changed to + (a plus sign), while cmd+shift+L works as usual.