This is what I have so far for my code. I attempted a DTD, but I don't know if this is right. Can someone help me write a DTD for my code? I'm new at this, so I'm sorry in advance if I don't get it right off the bat!

<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<!DOCTYPE catelogs

[

<!ELEMENT catelogs (qtyelement, catelog )>

<!ELEMENT company (mainqty, catnbr, itemdesc, itemcost)>

]>
<?xml-stylesheet type="text/css" href="CatelogDescriptions.css" ?>
<?xml-stylesheet type="text.css" href="invoices.css" ?>
<!--
Name: Moriah King
Lab Number: 7
Well formed: yes
Valid: Yes
Other Browser: Google Chrome
-->
<!-- This document is for catelog item -->



<catelogs>
<qtyelement>3</qtyelement>
<catelog>
<company>®Signature Photography</company>
<mainqty>3</mainqty>
<catnbr>CSDR415</catnbr>
<itemdesc>Model D3 Toykon DSLR camera</itemdesc>
<itemcost>1699.99<qty>1</qty></itemcost>

<catnbr>AQUF895</catnbr>
<itemdesc>Raystop UV filter</itemdesc>
<itemcost>295.95<qty>2</qty></itemcost>

<catnbr>TBLS452</catnbr>
<itemdesc>Model v400 Toykon lens</itemdesc>
<itemcost>449.95<qty>1</qty></itemcost>
</catelog>

<catelog>
<company>®Deep Water Aquariums</company>
<mainqty>5</mainqty>
<catnbr>TFDI104</catnbr>
<itemdesc>Tandom 50 gal tank</itemdesc>
<itemcost>23.95<qty>3</qty></itemcost>

<catnbr>TFFD413</catnbr>
<itemdesc>Bora Trop Fish food</itemdesc>
<itemcost>14.65<qty>1</qty></itemcost>

<catnbr>TFCR007</catnbr>
<itemdesc>Bora 50 gal tank filter</itemdesc>
<itemcost>1.50<qty>1</qty></itemcost>

<catnbr>TFSC738</catnbr>
<itemdesc>Amazon sword plant</itemdesc>
<itemcost>4.95<qty>1</qty></itemcost>

<catnbr>TFGR109</catnbr>
<itemdesc>40 lbs natural gravel</itemdesc>
<itemcost>6.48<qty>2</qty></itemcost>
</catelog>

<catelog>
<company>®Toy Soldiers</company>
<mainqty>1</mainqty>
<catnbr>CSLN053</catnbr>
<itemdesc>Bends model 44 remote control sailboat</itemdesc>
<itemcost>658.25<qty>1</qty></itemcost>
</catelog>
</catelogs>