EDIT: two people have made comments about the length of this. Sorry, but when you have an intern, to manage them well in almost all cases is going to be lots of work. If this answer is too long to be effective for you then you are going to have serious patience issues working with interns.
My experience is the overwhelming majority of managers in all fields (especially technical fields) are quite poor at managing interns well. If this wasn't the case this answer would have been a lot shorter.
Neither of the other current answers addresses how to create an environment which does this
I want him to feel like he can come to me with issues.
This is a huge important part of the question and one which quick "short answers" are not going to be able to easily address.
Preparation for an intern - what to know
It sounds like you are going to be the day-to-day person responsible for the intern. Before I even begin, let me say - you are going to have a huge effect on how this intern views your company and their experience, and the intern is going to take a ton of your time initially.
Let me say this again: your actions/inaction will strongly affect the intern, more than you realize, and require a ton of your time.
Most managers/mentors make the mistake of treating an intern as a full-time employee. This is a bad idea for a variety of reasons, but the key reason is:
- Interns normally have limited/no work experience and limited school experience
What this means practically is interns have no idea how corporate environments operate. This is manifest in more ways than I can possibly hope to list, but there is a large difference between an academic environment and a corporate environment. The intern will have the majority (15-20 years vs 0-12 months) of their experience in an academic environment with constant feedback and well defined projects/homework.
So, with respect to the above, you must remember
- Interns won't have a good feel for "corporate culture" (and, even if so, probably won't know your culture).
- Interns almost never work on projects longer than 1 semester given academic terms.
- Interns have received constant feedback for nearly two decades on all their schoolwork/projects. Homework gets grades. Larger projects are broken into week or two week deliverables, etc.
- Many interns are closer to high-school than being college graduates.
- Most interns never have had a manager before, and normally if so, it's in a service environment (retail, food service, etc) and not an office environment, and will not understand how communication with managers works
Execution - what to do with an intern
Ok. So now you know this and you have met your intern and have shown them around, introduced people and coworkers, shown them where the bathrooms are, fought your IT department to get them a computer setup, bought them lunch (pro-tip: college students can be bought easily with $5 worth of food), introduced them to the projects they will be working on or at least the background information. Now what. (first make sure you do this).
The first thing you do is establish a meeting with your intern. A minimum of once a week. The purpose of this meeting is to ask your intern how things are going and make sure they know they can communicate any problems or issues they are having. but enderland, how do I make sure they know this is the purpose?! You can just tell them. It's probably better if you have an official weekly meeting but make an effort of asking your intern "how is learning that new tool going?" or "how'd that task go?" or something similar each day
Second, figure out how your often and how intern wants feedback, guidance, and answers to the, "am I doing a good job?" question. I'll answer it for you initially - much more often than you can possibly imagine. But enderland, employees don't normally get feedback from bosses often in the real world. Correct - but remember what we talked about above. Interns don't know this and their entire world for several decades has been centered around constant feedback. Make sure to be aware of this and give feedback or encouragement.
Now, some interns will not want this, which is fine. But make sure to assume interns want considerable amounts of feedback. Most do, but almost all won't say anything to you about it unprompted. Don't act as if they don't unless you talk about this specific issue with them.
Third, try to figure out whether your intern is too busy or not. Most interns won't know to ask for more work but rather sit being bored. The flip side is most interns will freak out if you overload them with work. Be mindful of this.
Fourth, don't assume anything about your intern. Many managers make the mistake of thinking their intern is having a great experience because they haven't said anything or complained or asked for more work. This is not necessarily true at all. Many interns will not initiate this sort of communication because they have no experience in the workplace. Most managers make the terrible mistake of assuming their intern will communicate as if they were a full-time employee.
The trend for interns (or tl;dr)
This could all be summarized as communicate, initiate communications, and communicate more than you think is needed. This doesn't matter if you are talking about training or any other element of your intern's experience.
This answer and this answer to different questions contain very relevant content as well.