i18n l10n – How do you translate the body text on a multilingual site?

I feel like this must be a daft question as I can’t find any reference to it on the internet so figure the answer must be obvious.

Here goes…

Do I have to manually copy text into google translate then paste it back into my articles to translate it to a different language?

The site is drupal 8.9.15 and I have enabled the language module and also the configuration, interface, and content translation modules.

After enabling the modules I then installed Spanish and have the following setting in Detection and selection.

Detection and selection image

URL selection

I have then enabled the following custom language settings and gone through each one to enable the desired options.

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I then go to an article and click on translate.

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The language dropdown switcher changes to the translated language and some of the interface also translates but none of the content.

Any help would be great
Thanks
Ben