Step 3: Building the final part of the arch.
After the walls are finished, you will begin slanting the bricks inwards towards a peak. This is difficult and will require a lot of skill, or somebody to help you hold the bricks (can only be done solo after the 2nd floor because only one person can fit on the roof of the 1st floor) Slant as shown in the video and then fill the gap shown in the photo with slop. Keep adding slanted bricks until the arch is complete.
Once the two walls meet, support from another person will not be needed because the walls will be able to support themselves because this is an arch.