1. Create account in one of these projects.
2. Search whether your prefered article topic has been written about. If for example I want to write about 'alarms' in Swahili, I will check 'kingora' which is the swahili equivalent for the same.
3. Write the article about the topic in that language. If you do not know it, write in English and ask someone to translate it.
4. Upload the translated article to Wikipedia.
5. Add your backlink url with prefered anchor text