fcp 8.1 after i oppen multicam clips i cant collapse them

You don't collapse multicams in FCP, they open into the Timeline pane into what's called the Angle Editor. You can't close that pane, you can only open something new into it. Like a project, or compound clip.

Open your project from browser.

What do you mean by collapse? Do you mean the term used in legacy FCP to convert the multicam edit to original source clips? That feature in not in the current FCP software.