Full Idea
Kant says that instead of focusing on the nouns 'time' and 'space', it would be more on target to focus on the adverbial applications of the concepts - that we don't experience things in time and space so much as experience them temporally and spatially.
Gist of Idea
We should treat time as adverbial, so we don't experience time, we experience things temporally
Source
report of Adrian Bardon (Brief History of the Philosophy of Time [2013]) by Adrian Bardon - Brief History of the Philosophy of Time 2 'Kantian'
Book Reference
Bardon,Adrian: 'Brief History of the Philosophy of Time' [OUP 2013], p.33
A Reaction
Put like that, Kant's approach has some plausibility, given that we don't actually experience space and time as entities. To jump from that to idealism seems daft. Does every adverb imply idealism about what it specifies?