Clean the window and the panes of glass. Let dry. Paint stripes around the frame with black paint and a large brush. They don't need to be exact. Let dry.
Measure the glass panes with the ruler. Cut the lace and chalkboard cardstock to fit the panes with the ruler and scissors.
Add the lace. Brush a layer of Mod Podge on one of the panes. Lay the lace onto the coated pane and lightly press down.
Apply a thicker coat of Mod Podge over the lace and let dry.
To add the cardstock, apply a thin layer of Mod Podge onto a pane and press down. Use the brayer to smooth (don't let the Mod Podge get onto the front). Let dry.
For the center pane cut several book pages, apply a layer of Mod Podge to the glass, and smooth them down one by one. Overlap as needed and let dry. Repeat until the window is covered. Go back and apply a coat of Mod Podge to the entire frame, minus the chalkboard cardstock. Let dry completely.
Add spiders with hot glue to your window, randomly as desired. Let dry completely before displaying.
Prep the chalkboard panes as instructed with a piece of chalk.