Click the hamburger men (three lines) in upper right and select 'New Account' and follow the prompts. If you are seeking more advice, please provide more information on your email account. Thank you.

Hi Mozilla Support form, Thank you for responding to my problem. Thunderbird did not recognize my email: Ido1@actcom.net.il... How can I add it to your email program ? Regards, Ido.

Setting up an account requires information on the account. That includes the name of the incoming server and outgoing server, port numbers, and security settings. Normally, the user has that after acquiring the email account from email provider. In a quick search, it appears that this is your email host: https://www.actcom.net/contact-us.html They should be able to provide information to set up an account on a PC. With that information, I will be glad to assist you.