Hi daleroberts,
For help with opening windows from a previous session in Safari, check your settings with the steps below found in the article here: Control which windows Safari reopens on Mac
"Check settings
When Safari opens, it might automatically restore the same windows or tabs that were open when you last quit Safari.
If you want to change this behavior, take either of these steps:
After you configure the system setting, check Safari settings as well:
- From the menu bar in Safari, choose Safari > Settings (or Preferences).
- In the General pane, choose a setting from the “Safari opens with” menu.
- If you set Safari to open with a new window, use the “New windows open with” menu to define which window or tabs Safari should reopen."
Also, you'll want to be sure Safari is up to date by ensuring you have the latest macOS as well. If needed the guide page here can assist: Update to the latest version of Safari
Depending on the macOS version installed you can also find helpful details for viewing past websites here: Go back to webpages you already visited in Safari on Mac
You can change the macOS version from the drop down menu, if needed.
Cheers.