please how to add existing yahoo online mailbox ? where to start/what to do ?

my yahoo account is an existing online account; what should I do to integrate it in EM Client; what are the steps ? thanks;

Go to menu/tools/accounts and click on the “+” sign on the bottom left of the screen.  The automatic setup should work (although I have not set up a Yahoo account), simply enter your email address and go from there.  If automatic setup doesn’t work, select email and then Yahoo.

It downloaded my yahoo mails but it continuously pops up a server unauthorized message (I suppose it tries to synchronize now and then); even when I set up yahoo mail to allow unsecure apps