Thanks for reaching out to us. We are very pleased to assist you.
According to the information you provided and the research I have done, I may understand that you want to create sites in Microsoft SharePoint Foundation. If there is anything wrong, please correct me.
If there is not anything wrong, it is suggested that you please try the following solution:
Microsoft SharePoint Foundation is a version of SharePoint Server. In SharePoint we can create site collections and sub-sites under a site collection. For more information about site structure in SharePoint, you can refer this article: Overview of sites and site collections in SharePoint Server.
For creating site collections, please refer to the steps in this article: Create a site collection by using Central Administration.
- For creating sub-sites under a site collection, please refer to the steps in this article: How to Create a Subsite in SharePoint 2016. SharePoint 2016 and Microsoft SharePoint Foundation are both SharePoint Server and they have similar interfaces, so we can refer to SharePoint 2016 to create sub-sites. Note: Microsoft is providing this information as a convenience to you. The sites are not controlled by Microsoft. Microsoft cannot make any representations regarding the quality, safety, or suitability of any software or information found there. Please make sure that you completely understand the risk before retrieving any suggestions from the above link.
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