Where to download the plugin manager from?
I just installed the 32 bit notepad++ but there was no plugin manager. Is that normal?
With current N++ versions yes.
You may read https://github.com/bruderstein/nppPluginManager/issues/80 on that. To install it manually take https://github.com/bruderstein/nppPluginManager/releases/tag/v1.4.11 (for 32bit PluginManager_v1.4.11_UNI.zip) and see https://bruderste.in/npp/pm/#install.