How to assign a method to the selected element?

Question

Vue.js

Hello! Please tell me how to organize the launch of a certain method when you click on the "generate graph" button after selecting an element from the list (screen in attachment)
here is a piece of code

<md-card-content>
         <div class="md-layout md-gutter">
      <div class="md-layout-item">
        <md-field>
          <label for="movie">график</label>
          <md-select v-model="graph" name="graph" id="graph">
            <md-option value="Summary_Invoices">Счета</md-option>
            <md-option value="Summary_Sales">Продажи</md-option>
            
          </md-select>
        </md-field>
        {{graph}}
      </div>