How do I put seats on only one side of a long table?

Select the table and choose One side in its seating layout. Every seat moves to that side, facing the same way, which is what a head table, a top table or a dais needs. Rotate the table so that side faces the room.

The seat numbers run along the seated side from left to right; change the direction with the seat numbering control if your place cards are printed the other way.