<ol>

<ol> represents a list whose order matters, such as instructions or a ranking. Its direct content consists of li items and permitted script-supporting elements.

Steps with a starting number

The list continues a sequence from step 3. The numbers come from the list, not manually typed text.

<ol start="3">
  <li>Open the document in a browser.</li>
  <li>Change one CSS value.</li>
  <li>Reload and compare the result.</li>
</ol>

li {
  margin-block: 0.5rem;
}

Attributes and nested lists

start is an integer ordinal, including when type uses letters or Roman numerals. type supports 1, a, A, i, and I; use it when the numbering form matters to references in the document. For a visual marker style, CSS list-style-type is usually suitable.

reversed is Boolean: its presence counts down, even if written reversed="false". A li’s value can set a particular item’s ordinal. Nest another list inside a li, not as a direct child of ol.

Try a change

Add reversed and start="5", then inspect the numbering. Use ul when reordering the items would not change their meaning. Marker appearance alone does not turn an unordered list into a meaningful sequence.

Sources and browser support

MDN: ol describes the syntax and links to the specification and compatibility data. Check individual values in that table when supporting older browsers.