Apply-PnPProvisioningTemplate : Object reference not set to an instance of an object. 2 questions here: how to control the order vertically, and how to place the web part to the main area or the sidebar.

<pnp:Page Url="{site}/SitePages/default.aspx" Overwrite="true" Layout="Custom">
          <pnp:WebParts>
            <pnp:WebPart Title="header" Row="1" Column="1">
              <pnp:Contents>
                <WebPart xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.microsoft.com/WebPart/v2">
                  <ZoneID>wpz</ZoneID>
                  <PartOrder>8</PartOrder>
                </WebPart>
              </pnp:Contents>
            </pnp:WebPart>

            <pnp:WebPart Title="Info" Row="1" Column="1">
              <pnp:Contents>
                <WebPart xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.microsoft.com/WebPart/v2">
                  <ZoneID>wpz</ZoneID>
                  <PartOrder>9</PartOrder>
                </WebPart>
              </pnp:Contents>
            </pnp:WebPart>

            <pnp:WebPart Title="Announcements" Row="1" Column="1">
              <pnp:Contents>
                <webParts>
                  <webPart xmlns="http://schemas.microsoft.com/WebPart/v3">
                    <metaData>
                      <type name="Microsoft.SharePoint.WebPartPages.XsltListViewWebPart, Microsoft.SharePoint, Version=16.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" />
                      <importErrorMessage>Cannot import this Web Part.</importErrorMessage>
                    </metaData>
                    <data>
                      <properties>
                        ...
                      </properties>
                    </data>
                  </webPart>
                </webParts>
              </pnp:Contents>
            </pnp:WebPart>

            <pnp:WebPart Title="Calendar" Row="1" Column="1">
              <pnp:Contents>
                <webParts>
                  <webPart xmlns="http://schemas.microsoft.com/WebPart/v3">
                    <metaData>
                      <type name="Microsoft.SharePoint.WebPartPages.XsltListViewWebPart, Microsoft.SharePoint, Version=16.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" />
                      <importErrorMessage>Cannot import this Web Part.</importErrorMessage>
                    </metaData>
                    <data>
                      <properties>
                        ...
                      </properties>
                    </data>
                  </webPart>
                </webParts>
              </pnp:Contents>
            </pnp:WebPart>
            <pnp:WebPart Title="Documents" Row="1" Column="1">
              <pnp:Contents>
                <webParts>
                  <webPart xmlns="http://schemas.microsoft.com/WebPart/v3">
                    <metaData>
                      <type name="Microsoft.SharePoint.WebPartPages.XsltListViewWebPart, Microsoft.SharePoint, Version=16.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" />
                      <importErrorMessage>Cannot import this Web Part.</importErrorMessage>
                    </metaData>
                    <data>
                      <properties>
                        ...
                      </properties>
                    </data>
                  </webPart>
                </webParts>
              </pnp:Contents>
            </pnp:WebPart>
            <pnp:WebPart Title="Menu" Row="1" Column="1">
              <pnp:Contents>
                <WebPart xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.microsoft.com/WebPart/v2">
                  <ZoneID>wpz</ZoneID>
                  <PartOrder>6</PartOrder>
                </WebPart>
              </pnp:Contents>
            </pnp:WebPart>
          </pnp:WebParts>
        </pnp:Page>