Q. Where should I install the yantras/items ?.

A.  It is generally recommended that a Yantra be placed in the north/north-west direction facing the south/south-east direction in a room. However, this rule of thumb does not apply to the Vaastu Yantra as it is supposed to be placed in the south-west corner of the house, facing north-east. The Sri Yantra is supposed to be placed in the east, facing west. The Lord Kuber Yantra should be positioned in the north facing south or in the east facing west.
 
Placing of two or more Yantras together

Two or more Yantras may be placed together but caution is advised that a Lord Kuber Yantra must always be positioned at the extreme left of any group of Yantras. This particular Yantra should be on the left-hand side when we look at the Yantras. The Sri Yantra should be in the exact center of the group. If an altar has only the Sri Yantra and a Lord Kuber Yantra, then the Sri Yantra should be to the right-hand side of Lord Kuber when we stand or in front of them. A Ganapati or Ganesha Yantra should always be placed at the extreme right side of any group of Yantras.