If I have a folder with 50 items in it on my cloud storage then the same folder goes to upload automatically to the cloud storage with 150 items instead will it overwrite those 50 original items please?

Hope this makes sense.

Thanks.

Yes it would. If you want a folder with different contents, I'd duplicate that folder on your local drive and make the changes you need. This way, you'd have the originals and the changes. And, the cloud would reflect that.

It will