Don't complicate things for him seeing as he's new to it, you can just do:
0) onActivate - Client - VCE_ifVariable [lastmsg] [==] [Hi there Bot!] []
1) onVariableTrue - Client - ChatMessage:"<color:FFFFFF>Hello, <color:FFFFFF>%1<color:FFFFFF>! How are you today?"
2) onVariableFalse - Client - ChatMessage:"<color:FFFFFF>Hi there!<color:FFFFFF>...<color:FFFFFF>Well forget you! You didn't even say hi to me!
If you really want it to seem like you are having a conversation, and not have to type and then click, but click first, use:
0) onActivate - Client - [Hello, I am a brick.]
1) onChatMessage - Self - VCEretrocheck [ifLastPlayerMsg] [==] [Hi]
2) onVariableTrue - Client - ChatMessage [Hello to you too]
For if you want to actually seem like you are having a conversation with a brick.