[TASK] Add info text on how to use markers

Resources/Private/Language/de.locallang.xlf

@@ -189,6 +189,14 @@
 			<source>String</source>
 			<target>Zeichenkette</target>
 		</trans-unit>
+		<trans-unit id="bachend.markerUsageInfo">
+			<source>Usage information</source>
+			<target>Information zur Benutzung</target>
+		</trans-unit>
+		<trans-unit id="bachend.markerUsage">
+			<source>You can use a marker in your text like this: "Dear {MARKER}, we hope you are fine with us contacting you. Kind regards {ANOTHERMARKER}"</source>
+			<target>Sie können die Marker wie folgt in Ihrem Text benutzen: "Sehr geehrte {MARKER}, wir hoffen dass Sie mit unserer Kontaktaufnahme einverstanden sind. Mit freundlichen Grüßen {ANOTHERMARKER}"</target>
+		</trans-unit>
 		<trans-unit id="backend.no_extension" approved="yes">
 			<source>No template was registered.</source>
 			<target>Es wurde noch kein Template registriert.</target>

Resources/Private/Language/locallang.xlf

@@ -144,6 +144,12 @@
 		<trans-unit id="backend.marker.type.string">
 			<source>String</source>
 		</trans-unit>
+		<trans-unit id="bachend.markerUsageInfo">
+			<source>Usage information</source>
+		</trans-unit>
+		<trans-unit id="bachend.markerUsage">
+			<source>You can use a marker in your text like this: "Dear {MARKER}, we hope you are fine with us contacting you. Kind regards {ANOTHERMARKER}"</source>
+		</trans-unit>
 		<trans-unit id="backend.no_extension">
 			<source>No template was registered.</source>
 		</trans-unit>

Resources/Private/Templates/Mail/Index.html

@@ -60,6 +60,16 @@
 								</tr>
 							</f:for>
 						</table>
+						<div class="panel panel-info">
+							<div class="panel-heading">
+								<f:translate key="bachend.markerUsageInfo" />
+							</div>
+							<div class="panel-body">
+								<p>
+									<f:translate key="bachend.markerUsage" />
+								</p>
+							</div>
+						</div>
 					</div>
 				</div>
 			</div>