Okay, so for the latter part. It looks like you might be putting it all in one folder. If you look through the "My Daz 3D Library" folder, you should see stuff like "Data", "People", "Runtime", and stuff of the sort if it's a fresh copy/install. I'll break open Steven Hair by OOT just for example.
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The "Steven Hair" folder (right) has three folders. These are usually the most common. (This is usually a common installation approach for non-Daz store content). Just highlight all three in the Steven Hair folder and drag them into the My Daz 3D Library folder. Usually, this stuff isn't smart content related, so when in Daz you'll go to Content Library > My Daz 3D Library > People > Genesis 8 Male > Hair (since, in this case, since we installed hair) > OOT Steven Hair.
As for DIM, it's hard to tell without looking at what settings you have. That Steven Hair is DIM compatible (They usually have the "IM" followed by numbers. If you open DIM and select the box "Show Details", it should tell you where your stuff is being installed and where you can change it. I have my own set to the directory above.
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The in the left image should match the "Custom Path". I have it set to install to My Daz 3D Library. If you look at the inside of a DIM compatible folder (again, I'll use Steven hair.), it's almost the same as any other Daz Folder. In this case, it's shown in the first image. The DIM version of Steven hair has "Data", "People", and "Runtime". DIM just does the same process as above automatically. So, you find your Package archive for DIM. Settings > Advanced Settings > Downloads. Then drop your DIM file into that folder. Once done, cancel out of the settings page and hit the refresh icon in DIM (near the top right), and file should pop up there. Hit install or select all and hit start queue.
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One thing I forgot to mention is that you might need to change where Daz Studio itself looks for the content, I'd show you if I wasn't mid-render, but mgomez0077 explains it
here. Hopefully that helped some.