follow these step....

1.open cleven
2.at loading driver press
a.loading injection driver
b.enable monitor mode
3.then press the status bar to get to cleven main menu
4. at cleven main menu press the scan button to search any WEP & WPA AP in range....the default search time is 10 seconds...
5.after 10 seconds search (a popup will show search complete) press WEP button if you want to cracks WEP AP or WPA button for WPA AP...
6.if you pick WEP then press the WEP button...you will see a few AP listed below...now choose any AP you wanna cracked (highlighten)
7.then press the capture button below the AP list.....
8. a x-term will popup to show the capture to that AP....look carefully at the data...if the data keep getting collected then just waits until the data is at 30k-50k....this show that the AP is active...
9.now it the data is not collecting any then the AP is not active....
10.at this point you have to different way to do.....
10a.if the AP is active & the data is collected at 30k-50k then go back to cleven menu (closed the x-term) then press the cleven status bar & select decrypt captured...
10b.if the data is not collected then go back to cleven menu (without closing the x-term) & press the authenticate button...another x-term will popup showing it try to authenticate with the AP....it will show successfully authenticate or not...
10c.if successfully authenticate the x-term will not autoclose...if it fails then x-term will closed automatic...
10d.at this point go back to cleven main menu & press the inject button...another x-term will appears show it try to inject the AP....

i will continues if you have understand the step above...