The item you downloaded may not be to a proper scale.
Try Zoom Extents to see if your 3DWH component HAS been downloaded into your kitchen/house. Also look in the Component Browser to see if has been included there, but perhaps not been placed in the model. If you see it there, try dragging from the Component Browser into your model window.
Normal good practice is to download a 3D Warehouse item into a new SketchUp model. Check things like:
- is it vastly overdetailed? Many models are full of totally unnecessary detail for use just as part of another whole. Check in Model Info/Statistics how many edges and faces are in the model. If the numbers are in the hundreds of thousands or millions, it’s probably too many. Also, check the file size. More than (at most) a few hundred KB or a few MB is probably too much.
- is its component origin AT the origin?
- does it have excessively large textures applied?
What kitchen item have you tried to download? Can you either upload your kitchen model here (with the 3DWH model supposedly it it), or if it is too big, upload it to a file sharing service like Dropbox, OneDrive or Google Drive, and provide a link in your post?