From that article:
**If a spare tabernacle is not available, the norms permit the use of a closed ciborium, though constant supervision must be assured in order to avoid any danger of profanation. Exposition with a monstrance is never permitted on Holy Thursday.
The decoration of the altar of repose should be special, At least four or six candles or lamps, and preferably more, should burn around it and should be tastefully arranged with flowers, drapes, fine cloths, carpets and a judicious use of subdued electric lighting in order to create the necessary ambiance of silence and meditation. **