user12273: I'm very new to DaVinci Resolve and I'm still trying to figure out what DaVinci Resolve is good at and for what effects I should use other software.
The result I want to achieve is to see multiple clips at the same time (in the render product, not only while editing). Each quarter of the screen should show another clip.
My approach is hardly satisfying:
To achieve that I tried to have a video in a video.
I resized the first clip and made it small. But that makes the rest of the screen black and I couldn't find out how make the black part transparent in order to show another resized clip.
There must be an easier way (though my approach should work, otherwise it wouldn't be possible to replace a green screen). Any suggestions?
BTW: Where can I learn such basic things? There must be a place to go.
Note: I'm aware of the split screen feature, but this is not what I was looking for (because it splits the screen only to let the user compare different color versions).

user12218: You are on The right track! There is not a specific effect to accomplish what you want to achieve.  
The only way (unless there is a 3rd party plugin, I don't know about) is to stack the 4 clips on separate tracks in the edit tab. Select one of them open the inspector (panel on the top right of the edit page) scale down and adjust the placement.  The video clip on the video track below should become visible. 
[Added by Michael Tiemann as a friendly amendment: In the panel where the scaling information is displayed, there are also parameters for the anchor point.  By default, images are scaled from the center, which means you have to add in X and Y offsets to get each clip going to each corner.  Instead, you can set the upper left anchor point to be the upper left corner of the video, the upper right to be the upper right, etc.  Then, when you scale, each video clip will retreat to its own corner.  If you want to animate this effect, you can have one clip expand from its corner and go fullscreen by scaling back to 100%, and you can return it to its corner by scaling down to 50%.]
Good luck.

12273: <p>I'm very new to DaVinci Resolve and I'm still trying to figure out what DaVinci Resolve is good at and for what effects I should use other software.</p>

<p>The result I want to achieve is to see multiple clips at the same time (in the render product, not only while editing). Each quarter of the screen should show another clip.</p>

<p>My approach is hardly satisfying:
To achieve that I tried to have a video in a video.
I resized the first clip and made it small. But that makes the rest of the screen black and I couldn't find out how make the black part transparent in order to show another resized clip.</p>

<p>There must be an easier way (though my approach should work, otherwise it wouldn't be possible to replace a green screen). Any suggestions?</p>

<p><em>BTW</em>: Where can I learn such basic things? There must be a place to go.</p>

<p><strong>Note:</strong> I'm aware of the <code>split screen</code> feature, but this is not what I was looking for (because it splits the screen only to let the user compare different color versions).</p>
 12218: <p>You are on The right track! There is not a specific effect to accomplish what you want to achieve.  </p>

<p>The only way (unless there is a 3rd party plugin, I don't know about) is to stack the 4 clips on separate tracks in the edit tab. Select one of them open the inspector (panel on the top right of the edit page) scale down and adjust the placement.  The video clip on the video track below should become visible. </p>

<p>[Added by Michael Tiemann as a friendly amendment: In the panel where the scaling information is displayed, there are also parameters for the anchor point.  By default, images are scaled from the center, which means you have to add in X and Y offsets to get each clip going to each corner.  Instead, you can set the upper left anchor point to be the upper left corner of the video, the upper right to be the upper right, etc.  Then, when you scale, each video clip will retreat to its own corner.  If you want to animate this effect, you can have one clip expand from its corner and go fullscreen by scaling back to 100%, and you can return it to its corner by scaling down to 50%.]</p>

<p>Good luck.</p>
