Personally I have been a project manager in real life but not related to games, in a tiny group it's kind of easy to organize so I can leave you a few tips and perhaps you can actually solve that part yourself:
-First of all you need to know how much time does x member to do y action. Basically the artist how much time does he need to draw a picture, the programmer how much time does he need to code the picture, the story or interaction that generates it... and the writer how much time does he need to write a good quest/dialogue/interaction that makes sense.
-Try to maximize time while giving the team members a bit of "fresh air", basically try to not adjust time expectations to the minimum, if you try to push it then it is very easy to fail to meet the times and generate too much in the team.
-Remember to talk each day to the members of the group and ask them what they are doing, it's important to see that everything is being made within the expectations and if not try to minimize the effect of the retard.
-Don't leave alone a member that isn't advancing/working, one of the main problems that you will find is that perhaps a member for various reasons will try to delay work, on that case you will need to add pressure because as a project manager you can't accept big delays because of one member, at worst they will want to be paid without working and never do that, I have seen too many cases of paying and people leaving without working.
-Basically the objective of a project manager is to achieve the objective, in the case of a game it is to generate content, and that's why it's needed to coordinate everything in a team, for example think for a moment that you want to create a quest, if you think about it writing and coding perhaps can't be done at the same time, but perhaps it may be possible that the programmer can prepare all necessary steps so that he only needs to add the text to complete the quest, with this you are optimizing time.
Usually in a tiny team you won't need a project manager per se, in the sense that having that position is usually when a project has many members (I would say at least 8 or 10) and it starts to need someone that focus only of that, that or overly complicated projects that have production bottlenecks and many problems along the way of production, you would need someone to control that.
To end I will do a tiny resume of what I said:
1º Have estimations of the time needed to do x, that means all part of the process and try to optimize it.
2º Interact with the members of the team to see that everything is going well and if something happens be prepared
3º Try to always achieve the time limit, to do that you will need an adequate one, so don't rush your team members in the estimation.
4º It may be a good thing if all the team can talk with each other so that they have a direct interaction with each other.
Basically with this you can more or less coordinate a tiny team, the main problem is when the team is bigger or there are some production problems which makes it necessary to have someone in that position.
