The Grande isn't like other mopeds. You'll have to learn its peculiarities to work on it effectively. I do all the routine stuff on mine easily now.
The carburetor removal is a skill you will learn soon. You didn't mention if the plate under the carburetor on the swingarm is still there. People sometimes drop the filter screen there and then can't find it. You have to remove this plate to get the carburetor out easily. It must be replaced to protect the carb from road grime.
I can pull the engine out of mine in 20 minutes. It's something else to learn since you have to pull it to replace the points. You will need the special flywheel puller from vespasupershop.com for that task. It's no big deal since the engine by itself comes out easily enough and it isn't encumbered by the clutch being an internal piece. As a matter of fact the clutch is on the rear wheel!
Do a search here under "Vespa Grande" to find all kinds of stuff I've posted in the past.