diff --git a/docs/operation-manual.md b/docs/operation-manual.md
new file mode 100644
index 0000000..db1a871
--- /dev/null
+++ b/docs/operation-manual.md
@@ -0,0 +1,52 @@
+# Operation Manual
+
+## Adding a Monthly Fee Override
+
+Use this when the club decides to charge a different flat fee for a specific month — for example, a reduced fee during a short or holiday month.
+
+There are two independent dictionaries in [scripts/attendance.py](../scripts/attendance.py), one for adults and one for juniors. Edit whichever tiers need an override.
+
+### Adults
+
+Add an entry to `ADULT_FEE_MONTHLY_RATE` (line ~15):
+
+```python
+ADULT_FEE_MONTHLY_RATE = {
+    "2026-03": 350  # reduced fee for March 2026
+}
+```
+
+The key is `YYYY-MM`, the value is the fee in CZK. This replaces `ADULT_FEE_DEFAULT` (750 CZK) for members who attended 2+ practices that month. The single-practice fee (`ADULT_FEE_SINGLE`, 200 CZK) is unaffected.
+
+### Juniors
+
+Add an entry to `JUNIOR_MONTHLY_RATE` (line ~20):
+
+```python
+JUNIOR_MONTHLY_RATE = {
+    "2025-09": 250,  # reduced fee for September 2025
+    "2026-03": 250   # reduced fee for March 2026
+}
+```
+
+The key is `YYYY-MM`, the value is the fee in CZK. This replaces `JUNIOR_FEE_DEFAULT` (500 CZK) for members who attended 2+ practices that month.
+
+### Example: March 2026
+
+Both tiers reduced to 350 CZK (adults) and 250 CZK (juniors):
+
+```python
+ADULT_FEE_MONTHLY_RATE = {
+    "2026-03": 350
+}
+
+JUNIOR_MONTHLY_RATE = {
+    "2026-03": 250
+}
+```
+
+### Notes
+
+- Overrides apply to all members of the given tier — use the **exceptions sheet** in Google Sheets for per-member overrides instead.
+- After changing these values, restart the web dashboard (`make web`) for the change to take effect.
+- The override only affects the calculated/expected fee. It does not modify any already-recorded payments in the bank sheet.
diff --git a/scripts/attendance.py b/scripts/attendance.py
index cdd285f..61f9eab 100644
--- a/scripts/attendance.py
+++ b/scripts/attendance.py
@@ -18,7 +18,8 @@ ADULT_FEE_MONTHLY_RATE = {
 
 JUNIOR_FEE_DEFAULT = 500  # CZK for 2+ practices
 JUNIOR_MONTHLY_RATE = {
-    "2025-09": 250
+    "2025-09": 250,
+    "2026-03": 250   # reduced fee for March 2026
 }
 ADULT_MERGED_MONTHS = {
     #"2025-12": "2026-01",   # keys are merged into values