I bought a pan, I want to a chef!

Seriously, don't worry about stock.  Keep reading, watch some tutorials, RTM, etc.   You'll get there.

Teach yourself and be prepared to put in 20 years hard work before you see good results. If you can adapt quickly to a rapidly changing industry you may be able to make a living or part thereof.

Wait a little while, there should be a whole rash of "how to make millions shooting microstock videos" being hawked on this forum very soon.

Presumably you've already Googled for settings?  If not, do that.  Yes, it is complicated...

I do have an OM-5 but I'm not an expert on using it for video (I have Canons for that), but in general, what you need is to use a shutter speed that's as close to half the frame rate as you can get, so as the OM-D will default to 29 frames/sec (maybe that's really 29.97, I'm not sure) you're looking for 1/60th of a sec.

If you use the camera in pure video mode I have no idea what setting it will select, beyond 29 frames/sec, so it's best to use either Shutter priority and set 1/60th of a sec, or Manual.  If Shutter Priority, it will try and get a sensible aperture, and you can use the exposure compensation wheel to adjust as it suits you.  If Manual, just adjust the aperture to get the exposure but keep it on 1/60th sec.  If that can't get you what you want, change the ISO, but generally you want that as low as possible, unless depth of field is vital.

You need to give any user scope to colour grade it for themselves, so set the Picture Mode to Natural or Muted, the Enhanced and Vivid modes are overprocessed for video.

It's not going to be possible to change focus during recording - at least, not in any way that will give good results as far as I know - so you're limited to setting focus first, then just recording a scene.  Or at least, that's what I do.  Perhaps someone else knows a way.

You may be able to hand hold (the IS is good) if it suits the subject, street scenes or things that are dynamic, but I would suggest it's best to start with easier stuff like static scenes with movement in the subjects - and you'll need a tripod for that, with which IS should be off in my opinion.

Then just try it out.  Mount it on the tripod, turn IS off, get it focused, set Shutter Priority and 1/60th of a sec, press the Live View button and adjust compensation till it looks right to you in the screen.  Then press the red "Record" button and get some footage.  Press it again to stop.

As for software, get a copy of MPEG Streamclip - it's free - again, Google to find it.  You can do basic editing in it to remove the shaky bits at the start and end, and various other stuff.

Then export from MPEG Streamclip as follows (my suggestion anyway, others may differ):

File/Export to Quicktime - settings:

Compression: Apple Photo - JPEG (All sites will accept this)
Quality: 90% (Don't go above 95%, the result will be a huge file for no great benefit)
Sound: No Sound  (the camera microphone is not likely to be good enough)
Frame Size: 1920x1080 (unscaled)
Turn off "Interlaced Scaling"

You can create a preset in the program so those settings can be easily retrieved.

Then click on "Make Movie" and it will make a new file... a much bigger one, unfortunately, but something you can upload.

Leastwise, that's the sort of thing I do.  Others may do it in other ways of course but it's a start!

Best of luck...  don't expect great sales though.  Pond5 is probably the best site to start with, but SS are good too.

Have fun.

Sounds like you've had more training than I have!

As I said, I'm no expert - and it could well be you'd get perfectly adequate results just setting it in video mode and going for it, but I'm used to using a 5D for video and I like to be able to set everything up for myself, so I do the same thing with the OM.  Could well be the IS doesn't matter either, but generally I turn that off (if I remember) when on a tripod so same here.

Best of luck.

Good points - and that bit about ND filters is especially true, as the slowish shutter speed means you can end up using very small apertures like f22 (unless it's dark),  causing any sensor spots to become more visible, and those are hard to deal with in video unless you have professional software.

I would recommend using manual exposure when shooting video. Auto exposure can have some undesirable results. For example, if you're panning past something that is fairly dark like a cave, auto exposure will open up the aperture to compensate, overexposing the footage temporarily and then resuming normal exposure after the cave has passed. As you could imagine, this would be very distracting. Likewise - suppose you're recording a static scene and all of a sudden, a shiney white car moves past the camera. If left on auto exposure, the camera will close down the aperture to compensate, temporarily darkening the scene. The same thing will happen if you tilt the camera from ground level to a higher point to film a building or other tall structure. The inclusion of the sky in the frame will darken the footage somewhat. If you set the camera to manual exposure mode (if your OMD has one) you won't have these issues.