I lost my “home”page and filezilla question

Ok io am trying to get my post answered today since nobody answered yesterday..;-)

Hi, i have a couple of questions, if you go to my blog
https://jessicabyers.com/blog/ it says that the page cannot be found…i think i accidentally deleted that page so how can i get it back? i made another HOME page that is now called Welcome but i really want that info on the HOME page that is on the top….how can i fix this or do i have to uninstall and install WP again?

Another question: I have tried to upload another theme and it won’t show up correctly….on another forum someone told me to use filezilla to upload my file but i have no idea on how to use that, does anybody know how to use that and explain it to me? I use hostgator as my host and i don’t understand if i am going to upload my theme template to filezilla am i not then going to upload the template to hostgator in cpanel?

thanks for your help.

~Jessica