See here that we finished wrapping the strings around the blind but we left about 6-8” of string undone.
Now take the remainder of the string and go ahead and wrap the string between the bottom rail and the bottom slat. Repeat this step until all the remainder of the string is pretty much gone.
We ask that you do not to use, zipties, string, rope or anything to tie your blinds together. If you do this step you will not have an issue with the strings coming undone.