Redirecting to particualr page from data from a field

Hi

I am trying to set up a redirection button from my main page and am struggling to find any help on the code needed. All I need is for a user to input a number of the directory they are after ie 46573 and then the index page in the said directory to load up. I need to somehow take the data from the unsername field and add it to the redirect code. There is no need for any security in this process. I have spend hours on trying to find how to do this but it doesn’t seem to be used or needed much as there are no comments on how.

Examples:

username : 46573

which would then redirect to

[url]www.mywebsite.co.uk/46573[/url]

next person may be

username : 99872

which would then redirect to

[url]www.mywebsite.co.uk/99872[/url]

Thanks in advance for any help…….

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