Using variables in file references

[Goff]

I am trying to make an automated system, ideally i wish to use a variable that i collect from the user at the begining of th automated process in file/folde location lines of code. I am aware that this sort of variable use is possible but i am finding it difficult to get the correct syntax. I have tried to some code in my script in order to help the automated process.

My code looks like this:

message "Please select the correct Picture"
dir = "c:\geoff\Master\subfolder\" + str(ModelNumber),

But it won't work - i keep getting syntax errors. Has anyone got any suggestions??

Cheers

Geoff