Holy Thursday makes two important demands on the church: foot washing and the altar of reposition. The former doesn’t really make many demands on the space, but the place of reservation is very important, especially for a church that doesn’t possess a separate Eucharistic chapel:
§ 82 § Following the Mass of the Lord’s Supper on Holy Thursday the Blessed Sacrament is carried to a place of reservation. If the Blessed Sacrament is ordinarily reserved in a chapel separated from the central part of the church, the place of repose and adoration will be there.* If there is no reservation chapel, then a space for reposition with a tabernacle should be prepared for the occasion.
The starred note is from the CDWDS: Circular Letter Concerning the Preparation and Celebration of the Easter Feasts [PCEF] (January 16, 1988), no. 49: “For the reservation of Blessed Sacrament, a place should be prepared and adorned in such a way as to be conducive to prayer and meditation; that sobriety appropriate to the liturgy of these days is enjoined, to the avoidance or suppression of all abuses.”
The important thing is that the separate chapel, if part of the premises, is to be used. Otherwise, more preparation will be needed.
All texts from Built of Living Stones are copyright © 2000, United States Conference of Catholic Bishops, Inc. All rights reserved. Used with permission.
Catholic Sensibility 
Question: assuming there is the separate chapel, is the Blessed Sacrament just returned to the tabernacle, or is the point to have some other arrangement, so the tabernacle is empty? Neither the text nor the note seems very helpful here.
Do you know of anything that would shed light on this?
We have a separate chapel (very tiny, and located behind the sanctuary), but longstanding parish custom (from the time of a previous church, without separate chapel) is to repose the Blessed Sacrament elsewhere.
Rubric No.5, for Thursday of the Lords Supper in the Roman Missal states emphatically that, “The tabernacle should be entirely empty,..” before the Mass begins. Further see Paul Turner, “Glory in the Cross – Holy Week in the Third Edition of the Roman Missal”, pg. 59. Here in Nagoya, Japan, admittedly a large Church, we use the small weekday chapel, setting up a separate tabernacle there, as the for our Altar of Repose. If this isn’t possible then finding a small room, ‘the Crying Room’, or if the sacristy is divided into multiple rooms using one of those would be an option worth considering. The room should be large enough to accomodate the celebrant and servers when the process there with the Blessed Sacrament, and/or to allow space for half a dozen or more to spend time in adoration. The first principle to be observed is having an empty tabernacle in the main Church whether it is in the sancturary or easily seen from the main body of the Church, so as to focus on the liturgy of day.