Manage synchronisation process

I installed successfully creative cloud and lightroom/photoshop cc 2018 and LR classic cc a couple of weeks ago.

I migrated the catalogue of LR into the Adobe cloud, I found out that it also contains pics of my iphone.

I have also a lot of pictures on my iphone (snapshots of my children), but I do not want these personal pictures in the cloud.

The only thing I want to achieve is that my catalogue of LR cc is synchronised with my ipad and with my Imac (I have the luxury of having two operating systems; one on each computer). For that purpose I made a new catalogue of LR classic and archived the old catalogues on my desktop in a separate map. Therefore invisable for LR and Adobe (I hope).

Half of the space (500 mb) is now occupied with the old catalogue, including my pics on my iphone. Should I delete all the pictures in the cloud (how can I do that quickly) and than migrate the newly created catalogue to the cloud.

In other words, how can I make sure that only my 'new' catalogue, including the attached pictures will be in the cloud and that the old pictures in the cloud will be deleted.

Assistance will be highly appreciated.