Replacing 2" rear axle lift block... Help!!!

I bought a 09 Tacoma and it was wrecked and has a cracked rear axle lift block. I want to replace it myself.

I've tried to find some stuff on YouTube, but nothing really walks me through it, so any pointers would be appreciated.

Here's my plan.

1. apply emergency brake and block tires to prevent truck from rolling.
2. loosen and remove u-bolts from axle.
3. jack up/lift frame enough to remove cracked 2" block and replace.
4. lower frame and tighten u-bolts as previous.
5. Finished?

Do I need to put a jack under axle? I see some guys putting jack stands under the axle and even removing tires... Do I need to do that?

What am I missing?