Our puzzles are sent partially assembled. The puzzle is separated in parts that will fit the cardboard sheets, that fit the shipping box.
They are packaged in order: left to right, top to bottom.
When you remove your puzzle from the box, place the sheets on a table and lay them out in order. The top sheet is usually the center piece, (and sometimes also some center rows that didn't fit in the larger parts). The next layer will contain the upper left corner.
A bag of extra pieces is included with each order. A few of the extra pieces are for trying out pens on. The rest of the pieces are replacements. You will want to keep these until after your event. A guest may make a mistake when signing their puzzle piece, or once in a while a piece or two may go missing. The extra pieces may come in handy for just such an occasion. :)
To assemble a puzzle that is in separate pieces, such as after your event, the trick is to make sure all the tabs are facing the same direction.
For regular round tab puzzles, the tabs go up and to the right.
For heart tab puzzles, the tabs go up and to the left.
It helps to look at a picture of the puzzle to know the layout it should have. Refer to the listing you ordered your puzzle from for a photo of your puzzle layout.
Puzzle dimensions can be found here
Edges
Here are some pictures to help figure out the edges. They can be the hardest part.