I am trying to create a task list from a .stp file (sharepoint list template) that I saved and seems like is not possible, can someone help me....
After saving your list as a template, the template .stp file would be saved in the list template gallery: https://yoursite/_catalogs/lt/Forms/AllItems.aspx.
To create a list from this template, you just need to go to the site contents-> add an app. Search for your tempalte and choose it.
I assume your problem is you can't see where to upload the list template (.stp) cause in modern its not enabled by default.
So to allow it on a modern template you need to enable it. You first need to download the SharePoint online management Shell for PowerShell then run the ps snippet below
Import-Module Microsoft.Online.SharePoint.Powershell $tenantName = "yourTenantName" $SiteURL ="https://$($tenantName).sharepoint.com/sites/yoursite" Connect-SPOService -Url "https://$($tenantName)-admin.sharepoint.com" Set-SPOsite $SiteURL -DenyAddAndCustomizePages 0
The solution was to search for the stp. file on the apps gallery, you basically go all the way to the end of your app gallery and your templates will be there, then you choose one of them and done! thank you everyone!