The answer is simple: when you have the time, money, role and onboarding process carefully detailed. It's simple, but not necessarily easy.
Let's break this down.
Role: the duties and responsibilities needs to be documented in a detailed job description.
Please don't go into a job site (like Indeed) and cut and paste a posted job description UNLESS it is exactly what you NEED. Clients often don't think through exactly what the person will be doing and estimating the amount of time it takes per week/month to do the work.
I recommend keeping a running list on paper for a few months of the tasks you think you can give to this resource, what inputs they need, what outputs are expected and the service level (SLA). If you need a certain task done by the X day of the month, that is a service level and we should be very clear about those expectations during the interview.
Think about what hours do you want them to work. Do you want them available when you are working? Will you allow them to work when it fits their schedule? This is very important to both of you and often an area which causes stress.
Things to keep in mind are:
Do you have written procedures for most if not all, the tasks you want them to do? You should!
Are all userid and passwords for systems handy?
Do they need special equipment to do the job? e.g. laptop, microphone, screens, desk, chair, place to sit, business cards, access to internal systems like Click-up, Asana, Quickbooks, HubSpot, etc.
Make a list their internal customers and colleagues contact information.
Time: it takes time to interview candidates, onboard and train them. Block times in your calendar - don't fly by the seat of your pants. Don't expect someone to "take notes" while you tell them what you want them to do. This is not fair to the person. They are nervous and often feel overwhelmed trying to make heads or tails out of what you just said.
Money: I suggest to my CFO clients that they set aside 3 months of what they are going to pay the person in a separate savings account. That's right. A separate bank account. Ahead of posting the job. Put 3 months salary in at one time or, better yet, every 2 weeks as a "payroll". This accomplishes two things. You will quickly find out if you can afford the new employee if you can make the bi-weekly payroll. Second, you have their first 3 months in the bank while they are coming up to speed. It takes time for an employee to be fully productive and you will feel less pressure if their pay is already accounted for.
If you follow these three suggestions, you are on your way to finding the right person, onboarding them well and paying them with less stress.
Simple, but not easy. Good luck!