Getting clips to match the same aspect ratio?

Hey, I'm trying to cut some clips together that were filmed on different aspect ratios. I'm curious if there is a way I can change them to all match without going through each one individually using smart conform. I've tried clicking on the project-clicking modify-then changing the resolution and it matches in size but doesn't change the aspect ratio if that makes sense. Fortunately they're not all far off from each other so I'm not too concerned about getting any distortion. If anyone could help walk me through this or throw out any suggestions it'd be much appreciated! Thanks!

I can change all fo that in the settings for a project. What frame size are you at now, and what do you want to change to?
Also, you can select lots of clips all at one time, then change the Conform to them all at once.
Or, create a new Project with the frame size you need, Select All / Copy from your original Project timeline, paste to the new one.

Hey Ben! Thanks for the advice! I figured out what you were talking about by highlighting each clip and using smart conform but unfortunately I hit more distortion than expected. Unless you have any other advice it looks like I'm going to have to find a perfect balance with using smart conform and letterboxing a tad. Let me know if I should give anything else a go! Thanks!

What frame size are your clips? Create a Project to that frame size.  Distortion?  Spacial Conform doesn't distort anything.  I'm a bit confused.