docs about query hints and parameters (#30)

Author: gdalecka

docs/cypher/index.md

@@ -1,7 +1,25 @@
 # Cypher
 
-TODO
+## Execution
 
+Queries can be executed either for Cypher file (in this case data source selection is required), 
+or from data source editor. To open data source editor, right click on data source and choose `Open editor`.
+
+Keyboard shortcut for query execution is *Ctrl + Enter* with the cursor on the query. Alternatively right click on 
+the query statement, select `Graph Database` -> `Execute Query`. 
+
+If query execution fails, an error hint is displayed. 
+![plugin screenshot](../screenshots/error_hint.png "Error hint") 
+
+The hint disappears as soon as any user interaction like mouse movement takes place.
+Afterwards it is possible to view the error details in `Log` tab.
+
+If parameters are needed for query execution, they can be provided in `Paramters` tab in JSON format.
+For instance, for query `MATCH (n) WHERE n.name = $name RETURN n`, parameter could look like `{"name": "Johan"}`.
+
+![plugin screenshot](../screenshots/query_parameters_sample.png "Providing query parameters")
+
+`Log` tab displays, what parameters where used for query execution.
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