The {{User WCUP}} template shows that the user is also a user of Wikimedia Commons and has a Wikimedia Commons User Page. It should not be substed. As a userbox, it was designed to be placed on a user page, where that user had the same name on Wikimedia Commons, so by default the main optional parameter takes the name of the page that it's placed on. (If Jimbo Wales put it on his user page, then it would state, "Wikimedia Commons has a User Page for Jimbo Wales".) If it is placed on a different page or if a user has a different username on Wikimedia Commons, an optional "user" parameter allows it to be explicitly given a specific username to link to. In addition, it has multiple optional parameters for formatting. The link to a userpage will never be a red link due to the nature of cross-project linking, so please check your work by previewing and following the link. Due to the limitations of cross-wiki linking, the links will continue to remain blue.
There are also several additional formatting options in the template. The following attributes are all implicitly assigned a value, but they may be changed by explicitly assigning them a value. Any attribute starting with "info-" refers to the text of the userbox.
If we wanted the textbox to float on the right, instead of float on the left, with a "gold" border, a "jolly green" background and text the color of "Harold's Crayon", then {{User WCUP | Jimbo Wales | float=right | border-width=9 |border-color=gold |info-background=#9CCB19 |info-size=20 |info-color=#B62084}} would give us that image which you see over on the right.
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