ho do i log into messages on my iMac?

[roowells]

hi,
im trying to log into messages on my imac, but the log in option is greyed out. how can i log in? thanks too

 

[FotoDirk]

At times some setting pages have this small lock icon at the bottom. Click it to unlock the page so that you can later it.

I have no Mac available at this moment to check, but if that is not the case, then first setup your iCloud account in the general preferences.

 

[eduardrw]

Start messages - for example type messages in the spotlight search box at the top right of your menu bar.
Once in messages goto Messages-Preferences accounts.
You should see the apple ID setup etc. Check that you have it setup correctly.