Are you talking about in Bolvangar?

The first hiding spot is immediately to your left under some crates.

Next, change into Wildcat, and do a Wildcat Dash to the second hiding spot (crates, ahead
of you on the right).

Next, change into Wildcat, and do a Wildcat Dash to the third hiding spot (crates, ahead
of you on the left).

it's not that hard it was under some table or under the oven

You never have to avoid the monkey.

In London, you have to sneak around when you exit your room and hide behind the cabinet
across from where you enter into the main hall area.

In the office, you're hiding from the maid or whatever and hide in the fireplace
(quickly).

Only in Bolvangar do you hide from the monkey.