[Newbies] Loading Vivide IDE?

[H. Hirzel]

Hello

I would like to load the Vivide IDE in the yet to be released Squeak 4.6.
(Preview here http://ftp.squeak.org/4.6/Squeak-4.6-All-in-One.zip)

On the Squeak ML I got the answer that I have to execute

Metacello new
  baseline: 'Vivide';
  repository: 'github://hpi-swa/vivide/repository';
  load: #(dev).
(Smalltalk classNamed: 'ViScriptArchive') mergeAll.

in a workspace.

However if I do that I get the answer 'Unknown variable - Metacello,
please correct or cancel'.


How do I bring Squeak 4.6 into a state where MetaCello is known?

Kind regards

Hannes Hirzel