Adding Ghost Text to LiveCycle Designer forms

Hi to all

i am new to coding and have been set a task of setting up a pdf form, but it requires ghost text to guide the users but also to allow them to type normal text when they fill in the form, so greyed out text for the ghost and black text for the completed field, but i have very little experience with coding and could do with some advice below is an examle of the text field i have in and would love to know what it is that i have to add to get this to work.

<field name="KnownMedicalConditions" y="76.2mm" x="66.675mm" w="127mm" h="6.35mm">

               <ui>

                  <textEdit>

                     <border presence="hidden">

                        <?templateDesigner StyleID aped0?></border>

                     <margin/>

                  </textEdit>

               </ui>

               <font typeface="Calibri" size="9pt">

                  <fill>

                     <color value="153,153,153"/>

                  </fill>

               </font>

               <margin topInset="0mm" bottomInset="0mm" leftInset="1mm" rightInset="1mm"/>

               <para vAlign="middle"/>

               <caption>

                  <font typeface="Calibri" size="9pt"/>

                  <para vAlign="middle"/>

               </caption>

               <validate>

                  <message>

                     <text name="formatTest"/>

                  </message>

               </validate>

               <assist>

                  <speak disable="1"/>

               </assist>

            </field>

            <?templateDesigner expand 1?></subform>

         <?templateDesigner expand 1?></subform>

      <subform w="576pt" h="756pt">

         <breakBefore targetType="pageArea" startNew="1"/>

         <draw name="G30" x="146.05mm" w="31.75mm" h="12.7mm" y="3.228mm">

            <value>