Structure for make chat app in android,ios,web with openfire

Hello

I am new in openfire.

I want to create chat app in android,ios and also in web.I setup openfire and it work fine with spark client.but confuse in how to make structure for manage all three platform together.

i google,and find some idea for this like

https://www.dbbest.com/blog/chat-application-solutions/

as per above link i make openfiredb and another one db.

now i have no idea to how to manage all this.

Please help me.

Thanks.