There are lots of options and keyboard shortcuts in atom. You don't need to learn them all, but the ones below will help you be more efficient. There's also a flight manual if you want to read more about atom.
|keys| result|
|------|------|
| PageUp
| move up a page |
| PageDown
| move down a page |
| Ctrl-g
| enter line number, move to that line |
| Cmd-Left or Ctrl-a
| move to beginning of line |
| Cmd-Right or Ctrl-e
| move to end of line |
| Ctrl-RightArrow
| move right one word|
| Ctrl-LeftArrow
| move left one word|
|keys| result|
|------|------|
| Ctrl-l
| select line (repeat to select multiple lines)
| Ctrl-Ins
| copy line
| Shift-Del
| delete line
| Shift-Ins
| paste line
| Ctrl-]
| indent line
| Ctrl-[
| unindent line
|keys| result|
|------|------|
| Ctrl-z
|undo
| Ctrl-Shift-z
|redo
| Ctrl-o
|open file
| Ctrl-n
|new file
| Ctrl-s
|save
| Ctrl-q
|quit
|keys| result|
|------|------|
| Ctrl-Shift-=
|increase font size
| Ctrl-Shift--
|decrease font size
| Ctrl-TAB
|go to next Tab
| F11
|toggle full screen