Keyboard shortcuts to control cursor focus

Hello everyone,
I’d like to navigate the mail-window completely by using the keyboard. Are there any hotkeys to set the cursor-focus directly to the left column (with accounts, mailboxes, quickfolders etc.) and another one to set the focus directly to the message-list? I didn’t yet figure out, if there is the possibility to define such special keyboard commands by myself?
Thanks for assist, best regards
Johann Christoph