[scripts] Add additional README info in sites

sites/README.md

@@ -15,3 +15,21 @@ Initiate a template by the following command:
 ```bash
 python tredprepare.py
 ```
+
+The scripts does a questionaired similar to the following:
+
+```bash
+Enter the locus name [HD]: PIEZO1
+Sequence motif [CAG]: TCC
+Number of motifs in reference [19]: 8
+Chromosomal start location (1-based) [chr4:3074877]: chr16:88733965
+Enter the FASTA path [/mnt/ref/hg38.upper.fa]:
+AGCCCCTCGTCCCTGGAG|tcctcctcctcctcctcctcctcc|TGCTGCTGCTGCTGATGC
+
+Template json file is written to `sites/PIEZO1.json`
+Please manually fill in the remaining details
+```
+
+The user will then need to modify the generated ``sites/*.json`` to fill in
+additional information - most critically, the ``cutoff_risk`` and
+``inheritance``. Please see the include ``PIEZO1.json`` for a sample JSON file.