iPhone/iCloud Storage

Hey. I have for a long time got trouble with the iPhones storage. I have bought extra storage for my icloud, but still I can't have more than 1-2 apps.

If I go to General > iPhone Storage - then it's full.

If I go to "my name" > iCloud - then I have a lot of space left (and I can see the storage space I bought).

Even if I got a lot of storage space on my iCloud, I still can't download any new apps. And I don't get it.

How can I get more space on my iPhone? And use the iCloud space I got?

How can I get/have more apps on my iPhone?

Please, help!