Yes, it is correct that you if you want to large volumes of data, you can gain quite some speed by disabling indexes and constraints and re-enable them afterwards.
But there is one exception: the clustered index. My experience is that is faster to have the clustered index in place when you do the load. And you example is exactly that: a clustered index.
Else, to disable all CHECK and FOREIGN KEY constraints is one single statement:
ALTER TABLE tbl NOCHECK CONSTRAINT ALL
To re-enable them, you run:
ALTER TABLE tbl WITH CHECK CHECK CONSTRAINT ALL
And, no, there is no typo, but it should be CHECK twice.
To disable an index, you say:
ALTER INDEX ix ON tbl DISABLE
You need to run this once for all non-clustered indexes: Whether they also are constraints does not matter.
To re-enable them, you can run
ALTER INDEX ix ON tbl REBUILD
for each index. You can also re-enable all in a single command:
ALTER INDEX ALL ON tbl REBUILD
But this will also rebuild the clustered index, so this will take longer time.