The larger issue is the frame size here. A simple Interpret Footage command on the 60 fps media changed to 24 fps will give the slo-mo. But you still have a smaller frame than 1920 x 1080 to deal with. Upscaling is not the best way to go. You may want to consider editing in a 720p/24 sequence, and downscaling the 1080 stuff.
I have to remain at 1080p 24fps. I have seen countless shorts shot with DSLR that have 720p 60fps footage converted/slowed down to 24 and integrated. Looked just fine.
Also, when I do interpert, the results is footage that doesn't look perfectly smooth like I am seing from examples converted with After Effects.
The problem for me is I am a complete beginner. So I can read and watch videos all day or all week long and if I cannot come across what it is I am looking for, I'm going to remain stuck. It doesn't help that I read so much conflicting information.
As I type this After Effects is opened, my footage is rendered to 24 fps and I cannot figure out how to save it as a file I can use. I'm just stuck and I hate feeling stupid.
Use Premiere Pro to do it
Import your 60fps clips into Premiere
then right click on the clip
then choose Interpret Footage...
then type the frame rate you want in the dialog box titled "Assume the frame rate is"
drag the clip to the timeline and you will playback in slow motion
I would reccomend rendering the clip so the playback is smooth, but otherwise everthing should work out fine
Do i have to do this for every clip? i thought premiere would have a way to do it faster....since FCP7 was conforming on cinema tools one by one , is there a way to do it as a batch?