Assembling a PDF is not complicated. All you need is some alone time, tape/glue and a flat surface.
- After you measured the test rectangle to make sure your pattern is printed at 100% scale, place your pages in numerical order (the page number is at the top of each tile)
- Fold / cut the top and left margin, along the border
- Using the diagram available on the first page as reference, tape or glue the pages row by row, using the edges and corners as guide
Some people keep the big sheet intact and trace off their size. Other people prefer cutting the piece so takes less space in storage. It's up to you and how you plan on using your sewing pattern.