Items can be placed on top of the table by holding the item, then right-clicking on the top of the table. A single-item container GUI can also be opened by shift-clicking the table with an empty hand. Items on the table can be rotated using a Tape Measure. The table will emit a light level that matches whatever item is kept on the table.
When two or more tables are placed next to each other they will merge into one table. This merging seems to go on indefinitely.