Personally I would rather tell other people what to do than follow orders myself. Many times I don't see what an authority figure of mine is doing, and I don't like doing things for them. But seeing that in a job, people tell you what to do, I like to know what exactly to do and when I have to get it done. Although it may appear that I do things without questioning it for a job, I don't like doing useless things for an organization. The type of ordering that is best is a list form, like a To-Do list.
Let me know if this helped, and any other questions you might have.
Thanks, it really helps!

I think the point there is that bolded up there. I have seen this in that ISTJ. I asked him to do something and he was almost doing it straight away. He does question things if he doesn't think it'll work. But that's totally ok. I can change the way I'm going in 1second. So, I don't mind about being right, I just mind about things going smoothly.
I heard him talking about his boss and it seems he respects authorities quite a bit (I don't by the way

).
I'm not his boss but he has to do things for the project I'm working in, so I need to ask him to do stuff.)
I was wondering how to ask him to do things:
Is it straightforward way: Do this and this?
Or does he want explantaion: Do this because of this?
(I myself need to always understand why I do things.)
Or would he appreciate me putting it this way:
Would you be so kind and do this as soon as you have time for it?
Alcea, when I'm in working mode I am pretty E. My husband is ISTJ. Here are a few things I try to remember when we are working on a project together.
He's a detail man but isn't very good at expressing his wants and needs. It's important for me to know when he says "Fix this" that he has in his head a mental list of the steps to follow and they generally aren't negotiable. There is one correct and efficient way to do something in his world.
So rather than assuming that my way will "fix" whatever needs fixing, I need to ask him to tell me step by step how he wants it done. The "
hows" of things are as important to him as having something done.
When a job is completed I have learned not to expect much praise. It's accepted as matter-of-fact that I did what I was supposed to do in his values system. Because he knows me well and knows what makes me happy, eventually he'll remember that saying, "Thank you. That was a good job" is a good idea to keep me in cooperating mode.
He, on the other hand, seems to thrive on
frequent and lavish praise and that spurs him on to stay on task.
Too much small talk or information will overwhelm him. When he hears, "We've gotta remember to do this, and this, and this." what he seems to hear in his head is "Right now!" and he goes on overload. So I try to dole out my own expectations in manageable pieces to him. He likes to be left alone to do his work.
Thanks Anja!
Let's see, I bolded some things in your post up there.
How's of things, yes - I see the importance of that.
And praise - yes, that's a bit surprising for ISTJ's as I think of them but I can do that. I mean, I'm pretty good in inspiring people even if my inspiring style might overhelm him pretty fast.

Ok, I'll try to keep that one under control...

So, I need to give him praise of the good job his done but not just because of nothing.
It's also becoming more and more clear to me that I will need to keep my Ne really well in control when speaking with him. So, always before speaking to him, I need to rearrange my thoughts in Te way so I can state them to him very clearly.
I've seen that he really likes our meetings when things are prepared and he sees the agenda first. But with spontaneous things, it's not very good because my Ne gets totally wild in seeing all the possibilites and I tend to think out loud. So, I can see that he doesn't understand that I'm merely seeing the possibilities and thinking options before I'm ready to do anything.
I can control my Ne pretty well when I'm prepared and the situation is not spontaneous action thing. So, I just need to be prepared with him and even with the spontaneous situations I need to arrange my thoughts before talking to him. That is going to be really hard for me!!
And boy I'm happy that I have trained my Te since the day I realized I'm the most messiest and disorganized person of all. The reality is, in these days, that my Te is probably much stronger that with an average ENFP althought it just might me my own imagination as usual!
But still, many potentially dangerous situations ahead....