Moving images/catalog from laptop with external drive to desktop master

I have a very specific way that I want to make this move.  I have shot 4000 images while traveling with my laptop.  My catalog is on the laptop's hard drive and all my images are in a separate folder on an external drive.  I want to first copy all my images from my external drive to a specific location on my desktop's drive - where I keep all my images that Lightroom uses.  Once this is done, (1) how should I move the catalog from my laptop into my master desktop Lightroom - and then (2)  "connect" this imported catalog with the new location where I have stored these images.  Also note - the folder containing the moved images contains more images than the collections moved.  I want to make sure my Desktop Lightroom knows about the large folder and all the smaller collections.  Don't believe that should be an issue - but wanted to be sure it's not. 

Thanks!