Step 1. Open up your package of dams. There will be 1 per grow shelf (total of 3 per Farmshelf).
Step 2. Apply light pressure to push the dam into place - at the back right corner of each shelf at the location of the drainage hole. Use one dam per grow shelf. When inserted correctly, the dam should stick up above the drainage hole about the height of a fingertip - as shown in photograph below. If you are applying hard pressure, then the dam is likely upside down.
Note. You should have dams already (that you may have temporarily removed at the end of a grow cycle in order to drain water from your shelves). We advise you to continue using those dams IN ADDITION to inserting the new dams. The photo below shows both the new dam and old dam. They serve different but related purposes and can work in tandem. Any questions? Please contact firstname.lastname@example.org