Sending a Kmail mail from another account

Hello,

I am new to OpenSuse. I used to use Ubuntu with Thunderbird for my mail. Now that I changed to OpenSuse and KDE I am trying to use the default applications. So I am trying to 'underestand' kmail. I think I almost got it, but still there is something I cannot do.

I have two email accounts. One of them is the default for sending messages, but if I want to choose the other account, how do I do it? I cant find anywhere except changing the default sending messages account.

I hope you can help me.

Thank you in advance!