Assembly Guide Activated Carbon Filter Step 1. Fill the filter with activated carbon until nearly overflowing. Step 2. Place the cover over the filter. Secure with four (4) M3 x 6mm SHCS. Filter Body Step 1. Fit the HEPA filter on to the cap. It should be a snug fit. Step 2. Note the arrow in the bottom left corner. Align the arrows on the cap and main body while pressing them together. Step 3. Secure the cap and main body with four (4) M3 x 6mm SHCS. Step 4. Place your radial fan over the fan inlet. The airflow symbol should be directly under the fan. Secure with two (2) M3 x 35mm SHCS. Step 5. Secure a filter to one side with four (4) M3 x 6mm SHCS. Step 6. Repeat with the second filter and four (4) more M3 x 6mm SHCS.