"How do I install a liner in a German helmet?" German Steel Helmets M35, M40 and M42: Find the rear seam on the liner band (the metal part). There will be a hole... place the liner in the shell and line this hole up with the rear hole in the shell. Install the first split pin (legs should spread out up-down); you'll have to wrestle with the inner leather band a bit, holding it out while you spread the split pin. Line up the 2 front holes in the shell and liner band, and install the last 2 pins (same as above). German Paratrooper Helmets: Identify the front and rear of the pad. The rear of the helmet has two holes, the front has none. First install bolts, with one nut only. Tighten. Place pad inside helmet, front forward. Yes, originals were glued to the shell, but it is unnecessary and makes adjustment difficult. Don't worry, despite a lack of glue, it won't go anywhere; unless you forget to install the liner.... Seat pad as shown. Note, the pad is NOT necessary. You may omit the pad if you want the helmet to fit a little lower on your head. Install liner frame. Seat band over the rear bolts first, then the sides on e after the other. Place chinstrap eyelets over each bold, then add the other 4 nuts.