add some help

components/OperonStructure.vue

@@ -210,7 +210,11 @@ function drawGene({ width, height }) {
 <template>
     <div ref="gbContainer">
         <v-card flat color="transparent">
-            <v-card-subtitle>model version : {{ structureVersion }}</v-card-subtitle>
+            <v-card-item>
+                <v-card-title>Operon structure</v-card-title>
+                <v-card-subtitle>defenseFinder model version : {{ structureVersion }}</v-card-subtitle>
+            </v-card-item>
+            <v-alert size="small" type="info" variant="text"> click on structure to visualize them</v-alert>
             <svg ref="svgRef" :width="computedContainerWidth" :height="plotHeight">
                 <g class="x-axis" />
             </svg>