Home page displays posts or its programmed content, not both; one page is inaccessible . . .

On my test website, regardless of theme template: Page one, so titled, which I assume is the homepage, is set to receive the latest posts; it consists of the title, a short text, and a picture. Page two, so titled, is the static page; it consists of the title, a line of text, and a picture. Page three, so titled, is another static page; it consists of the title, a picture, and a caption. Test post one, so titled, consists of the title and some text. Test post two, so titled, also consists of the title and some text. Test post three, so titled, consists of the title, some text, a picture, and a link. In wp-admin mode: When I call up page one to edit, the title, picture, and text appear; preview in new tab displays title, picture, and text—as well as header with tag line and menu (which, when accessed, displays link only to page three; and footer, which also displays a link only to page three as well as copyright slug. When on another computer I call up the website, I get the three test posts as well as the header and footer menu links to only page three. But no picture, except the one from test post three. When I click on the titles of any of the posts, the other two disappear. There is no way I can get the static picture on page one or get to page two. When I call up page two to edit, the title, picture, and text appear; preview in new tab displays title and text, but no picture; and same header and footer link only to page three. When I call up page three to edit, the title, picture, and text appear; preview in new tab displays title, text, and picture; and same header and footer only to page three. Why has page two disappeared? Settings for three posts are identical; settings for three pages are identical. And the two widgets that had been in a sidebar have for some reason been inactivated. I switched to another theme to put back the widgets, but the pertinent details remain. What am I doing wrong or not doing?