Add directory structure information to the README

README.md

@@ -1,2 +1,18 @@
 # darksidewalletd-test-data
 Test files (sample blocks and transactions) for full-suite integration zcash/lightwalletd-wallet tests
+
+## Directory Structure
+
+The block sets contained in this repository are organized as follows:
+
+- Related block sets should live in the same directory. The directory name
+  should indicate the type of testing that the block sets are useful for, e.g.
+  `basic-reorg` for basic reorg testing.
+- Inside the directory, there should be one or more `.txt` files containing the
+  block sets. There will usually be multiple block sets for reorg tests (before
+  the reorg, after the reorg). The filenames should indicate what the blocks are
+  useful for.
+- If the block sets were generated using the `genblocks` tool in `lightwalletd`,
+  then there should be a `generate.sh` script for re-recreating the input to
+  `genblocks`. This will save everyone time if the block sets need to be
+  regenerated or modified.