SEO Onpage + backlinks + different languages

We're a big website in the gaming niche and we're looking for someone to manage all our SEO in the long term for a monthly or weekly payment. Right now we only have the website in english but we're looking forward to translate it to different languages, so we would live advice on how to proceed SEO wise on that, we would also like to optimize our onpage SEO and then keep building links and get articles related to our niche for the long term. What can you offer, do you have experience with different languages? We're looking for someone who makes a custom proposal and we aren't looking for copy pasted introductions, if you stand out, we'll hire you. It would be a plus if you have some examples of websites you helped and increased in rank. You can ask me in PM about the website link and I'll provide it!