Next, you will select the seats, and then add the boat to your selection. Then you can join them.
On the header of the Properties window, select the Object button. It has the orange cube. It is the fifth button from the left.
Use the button shown at the bottom of the following graphic, in the Properties window, to change the name to
Seats. You can type it in and move the cursor away, or press Enter when you finish.
Save the Blender file.
Select the seats again with the RMB. Now press the Shift key when selecting with theRMB to also select the boat. Be sure to select the seats first.
Press Ctrl+J.
The seats and the boat are now a single object. Now look at what the name is.
Look at the Material panel in the Properties window. Note that the properties of all three materials are listed, since both objects have been joined.
Save the file to a unique name.