How to append a Tag in a existing XML as per count increases Dynamically through Data source

Hi wasnt able to understand it properly can u please give a detail on it please find updated Request XML

<InterfaceRQ xmlns="*****">
   <RequestHeader>
      <UserID>${#TestSuite#UserID}</UserID>
      <SessionID>${#TestSuite#SessionID}</SessionID>
      <TransactionID>${#TestSuite#TransactionID}</TransactionID>
      <SupplierCredentialsList>
         <SupplierCredentials>
            <SupplierID>${#TestSuite#SupplierID}</SupplierID>
            <Sequence>1</Sequence>
            <Credentials>
              
               <Credential name="${#TestSuite#CredOne}" isEncrypted="${#TestSuite#Encyp}">${#TestSuite#USERNAME}</Credential>
            
                <OperationURLs>
                  <OperationURL operation="all">${#TestSuite#OperationURL}</OperationURL>
               </OperationURLs>
            </Credentials>
         </SupplierCredentials>
      </SupplierCredentialsList>
   </RequestHeader>
   <RequestBody>
     <OTA_TourAvailRQ>
      <ProcessingInformation PricingCurrency="${#TestSuite#PricingCurrency}"/>
            <Tour>
             <Location>
                  <Address>
                     <CountryName Code="${#TestSuite#CountryName}"/>
                  </Address>
                  <Region RegionCode="${#TestSuite#RegionCode}" />
               </Location>
               <Schedule StartPeriod="${#TestSuite#StartPeriod}" EndPeriod="${#TestSuite#EndPeriod}"/>
             
            
                <Participant Quantity="${#TestSuite#Quantity}" Age="${#TestSuite#Age}">
                  <QualifierInfo Extension="">${#TestSuite#Extension}</QualifierInfo>
                  <!-- Value Can be Adult,Child,Infant -->
               </Participant>
                
              
            </Tour>
         </OTA_TourAvailRQ>
   </RequestBody>
</SightSeeingInterfaceRQ>