In windows, to add a tab to the left of 3 or 4 lines, I've settled into the habit of doing either one of two things..

1. Up, Home, Tab, Up, Home, Tab, Up, Home, Tab, Up, Home, Tab.
Which goes up per line, heads to the far left, then places a tab.

or
2. Select all lines, hit Tab.
Which adds a tab to all the lines.

On a Mac, my fingers are exercised a little more thoroughly...

-=-=-

1. If I do my usual Up, Home, Tab, Up, Home, Tab trick, the Home button instead flings me right up to the bloody top of the text file, losing my place, and wasting a few seconds to do it.

Instead, on a Mac, you're meant to use Winkey+Left (or Left Amiga, or whatever the squiggly doodle is meant to represent on a Mac.. Because "Squiggly Doodle" is the only thing that leaps into my mind, without me being explicitly told it's name.)
Winkey+Left jumps to the far left.
So, on a Mac, you do...
Up, Hold Winkey Tap Left, Let the fuck go of Winkey, Tab, repeat.
If at any point, you accidentally mistime your Winkey press, you'll either (Winkey+Up) Jump to the bloody top of the text file again, or (Winkey+Tab) flip to something completely different.
Either one will make you swear.

But wait, there's choice number 2!

2. Select lines, Hit Tab.
Which replaces all the lines of text with a single Tab.

FUCKING MAC!!!!

Instead, you must Select all lines, then hit Winkey + [, which are at opposite awkward sides of the keyboard.

FFS!