Any door or window that needs to be adjusted must has to be attached to a wall first. If you select an opening and the panel is blank, that's why. Drag it onto a wall until it snaps on, then select it again.
Doors
Type — Hinged (swings), Sliding (runs across the opening), or Pocket (slides into the wall, good for tight spaces). Changing type applies that type's standard width and height, so set the type first, then the size.
Size — Width and Height under Dimensions. Height is capped at your ceiling height.
Which way it opens — under Configuration → Orientation:
Flip hinge side — hinges move to the other side, so it swings from the left instead of the right
Flip open direction — swings into the other room
Between them you get all four arrangements. Worth checking anywhere a door would open into a wall, a walkway, or another door.
Orientation only appears on hinged and pocket doors — sliding and garage doors don't swing. Garage doors also have no type selector, since they can't become interior doors.
Windows
Type — Hinged, Sliding or Blinds.
Dimensions — four values: Width and Height size the window, Sill height is how far its bottom sits above the floor, and Distance from ceiling is the gap above it.
They're linked, because the window has to fit between floor and ceiling. Change one and Maket adjusts another:
Change Height → the sill moves
Change Sill height → the window resizes
Change Distance from ceiling → the window resizes from the top, sill stays put
The rule that matters: whichever value you set last is the one that sticks. Set sill height last if you care how high the window sits; set distance from ceiling last if you want window tops to line up.
Finishes and removing
Both have a Finish under Design References — the material used when your plan is rendered in 3D.
To remove one, select it and click Remove door or Remove window. The wall closes up behind it.
A wall containing a door or window can't be made invisible. Remove the opening first, then hide the wall.