Can I have multiple diagrams mapped and merge them?

Question

I am very new to Mermaid and would like to write this image in Mermaid.

Right now I am learning all the functions and would like to start with the Actor for example. But I noticed that the Actor only works in the SequenceDiagram and wanted to ask you if it can be mapped at all or do I have to use a BlockDiagram or another diagram.

I have also posted my current code. What exactly is the R with the down arrow supposed to mean?

I am very grateful for your support.The Graph

mermaid
flowchart TD
    id1(Web Browser)
    WebServer["Web Server"]
        direction TB
        StaticHTMLPages[Static HTML Pages]
        DirectoryAgent[Directory Agent]
        PersistentData[Persistent Data]
    Actor--> id1
    id1 -->WebServer
    WebServer -->DirectoryAgent
    DirectoryAgent --> StaticHTMLPages
    DirectoryAgent -->PersistentData
    PersistentData -->DirectoryAgent
    StaticHTMLPages --> WebServer