writing to custom table or field

Hey I am just getting started, and I am able to write to core tables and managed fields,
In the first case i am trying to write to a custom table called lead:

{% form entity="zwp1_lead" mode="create" recaptcha=false %}

<form>

    <div class="form-group">

        <label>

            First Name:

            <input class="form-control" name="zwp1_firstname">

        </label>

    </div>

</form>

{% endform %}

I then just get the error ‘zwp1_lead’ not supported.

When I try to write to a custom field in the contacts table called x it doesnt write to that field, but all the other standard fields:

{% form entity="contact" mode="create" recaptcha=false message = "Thank for submiting we will get back to you soon" %}
<form>
    <div class="form-group">
        <label>
            First Name:
            <input class="form-control" name="firstname">
        </label>
    </div>
    <div class="form-group">
        <label>
            Last Name:
            <input class="form-control" name="lastname">
        </label>
    </div>
    <div class="form-group">
        <label>
            X:
            <input class="form-control" name="cr212_x">
        </label>
    </div>
    <div class="form-group">
        <recaptcha>
    </div>
    <div class="form-group">
        <button type="submit" class="btn btn-primary">Send</button>
    </div>
</form>
{% endform %} 

Assistance would be appreciated, really like the plugin.