The right sitemap for a bulletin board?

Question

PHP

Good day!
There is a bulletin board website.

How to properly organize the structure of the XML sitemap, given the fact that the "turnover" of ads is large?
Let's say the average ad relevance time is 1-3 days. After that, it is removed.
How to make a site map correctly so that the search engine "monitors" the map as often as possible?
For the relevance of the contents of the map is changing rapidly.

Thank you!

Answer 1

There are special search engine pinging services: www.vbizsoft.kg/seo/ping-search-engines.html
https://codebeer.ru/ispolzuem-ping-servisy/