Install the Language and Content Translation modules
The first step in making your site multilingual is to install the required modules.
Navigate to the extend page and select the Language and Content Translation modules, which can be found under the Multilingual bundle, then click Install.
Add a new language
After the modules have been installed, we can add the required new language(s) to the site.
Navigate to Configuration > Regional and language > Languages then select + Add language. Use the drop-down select list and either search or scroll down to select the new language then click Add language.
After you have added the new language, it will be visible in the languages list. You can add more languages to the list if required.
Language detection and selection
We have our new languages installed on our site, now we need to configure how the languages are detected and selected.
Navigate to Configuration > Regional and language > Languages > Detection and selection. As a minimum, you should have Selected language and URL selected. These options will allow both URL detection and selection through the language switcher block.
You can select more options here such as the User which selects the language based on the users preference or Browser which selects the language based on the users browser language settings.
Configure fields to be translated
Before we begin translating content, we need to configure the fields that will be translated.
Navigate to Configuration > Regional and language > Content language and select Content from the Custom language settings list.
Your content types will appear below. Click on each content type you would like to translate. The translatable fields will appear.. By default they will all be selected, however, a lot of the fields don't need to be translated for most content types. Unselect all the fields that you don't want translated. I suggest having text fields selected only, such as Title, Summary and Body.
Note: if you are translating Paragraphs don't select the paragraph reference field on the content type, instead select Paragraph from the Custom language settings list then select the fields to be translated underneath each paragraph type.
Our site is now configured and we are ready to translate content.
Navigate to the edit page of an existing node then select Translate from the Tabs section. The English translation of the node is at the top of the list, followed by the new languages that have been added to the site. Click Add on the language below English and then begin filling in the fields. You will only be able to see the fields that you had selected in the previous step. Once you have finished, save the node.
On the Translate page, you will now see that you have a node in two languages. Continue adding translations to your other nodes as required.