Moving to Production and Management.
Let's start with a realistic assessment. Are you sure you are ready to hire someone?
You wrote "open-world-mmo with RPG elements".
MMO has a meaning although it is frequently abused. If you really mean an MMO, a truly massively multiplayer experience supporting several hundred thousand concurrent players then you need a budget of around $100M. Unless you can afford to run colocation data centers around the globe, you probably don't mean MMO.
So I'll assume you mean an open world online game with RPG elements.
But then you also mentioned a game on the phone. That's good, because they are cheaper to develop.
A good game team for that vague description will be in the $500K to $10M range. You will need to hire several people, each in the roles of production, design, software, and art. The exact cost will vary based on your location on the globe. In the US game development hubs the cost is currently about $15K per person per month. That isn't just their wages, but the total cost of employment such as payroll support, taxes, occasional other fees, and government-mandated insurance.
Your first hires would be your senior development staff, meaning some people who can fit the role of producer, the role of designer, the role of either programming lead or project manager depending on naming, and the role of art director or art lead. These people will help you expand your ideas and craft it down to something within your budget, and they in turn will help you hire the people within your disciplines that you need. If you have more ideas than budget, you will need to hire people with skills in multiple disciplines. The people cost more in wages, but are also more valuable to the business.
But before you go hiring your staff, remember that usually development is about 1/3 of the total costs. Games need marketing to be successful, and marketing costs for successful small games will typically equal or exceed the development cost. So $270K to build it, you'll want another $300K to market the game to help ensure its success.
The other 1/3 of the costs tends to go into other costs as you explore ideas and for costs supporting the game and the team after development completes. Your online component means you'll be paying for servers and for server maintenance, you'll be handling customer support requests, and those take time and effort and therefore money.
So there you go.
If you have funds for (approximate monthly salary * 1.5) * (number of people) * (months in development) * 3, then start by hiring those four lead individuals (producer, designer, programmer, artist) and follow their advice.