"send to" reconfig after thunderbird install?

Installed Mozilla Thunderbird. Am happy with it other than two issues:
1.) now, when I click on an e mail hyperlink on a webpage, it says I must reconfigure send to because there is no default mailbox. How do I do this?

2.) When I type a hyperlink into an e mail message, it does not become a link, does not highlight, does not become active. How do I fix this?

Thanks and Blessings,
Port-O-San

 

Roy66 - thank you so much! followed instructions, fixed my ills.
Blessings,
Port-O-San:wave