<p>MDBStepper is not a function? I have PRO version selected.

<ul class="stepper linear">

  <li class="step active">

    <div data-step-label="Type something" class="step-title waves-effect waves-dark">Step 1</div>

    <div class="step-new-content">

      <div class="row">

        <div class="md-form col-12 ml-auto">

          <input id="email-linear" type="email" class="form-control validate" required>

          <label for="email-linear">Your e-mail</label>

        </div>

      </div>

      <div class="step-actions">

        <button class="waves-effect waves-dark btn btn-sm btn-primary next-step">CONTINUE</button>

      </div>

    </div>

  </li>

  <li class="step">

    <div class="step-title waves-effect waves-dark">Step 2</div>

    <div class="step-new-content">

      <div class="row">

        <div class="md-form col-12 ml-auto">

          <input id="password-linear" type="password" class="form-control validate" required>

          <label for="password-linear">Your password</label>

        </div>

      </div>

      <div class="step-actions">

        <button class="waves-effect waves-dark btn btn-sm btn-primary next-step">CONTINUE</button>

        <button class="waves-effect waves-dark btn btn-sm btn-secondary previous-step">BACK</button>

      </div>

    </div>

  </li>

  <li class="step">

    <div class="step-title waves-effect waves-dark">Step 3</div>

    <div class="step-new-content">

      Finish!

      <div class="step-actions">

        <button class="waves-effect waves-dark btn btn-sm btn-primary m-0 mt-4" type="button">SUBMIT</button>

      </div>

    </div>

  </li>

</ul>