How to build a shed:

Step one:  Order a butt-load of wood (huh huh, huh huh huh)

******VERY IMPORTANT!!!***** Step 2: Hire professionals.

Step 2A:
Watch as they build a foundation and level it on blocks:

Step 2B:  The pros (our extremely able friends Dave, Matt and Sylvia) install the floor

Step 2C:  Before you know it, a wall will be framed...

Step 2D: ... and another started.

Step 2E: Once all 4 walls are framed, you can call it a day.

On Day 2, Build a small attached deck and throw on some siding:

 Maybe add a few roof joists:

And throw on the initial coat of primer to prepare for final paint job, which will make the shed match the house.