Dear Forum users,

I am completely new in using Silverstripe. I have just installed the event calendar, userforms and dataobject manager.
Now I receive following errors:

Strict Standards: Declaration of DataObjectManager::FieldHolder() should be compatible with that of ComplexTableField::FieldHolder() in /users/tinchen1/www/dataobject_manager/code/DataObjectManager.php on line 4

Strict Standards: Declaration of DataObjectManager_Item::Link() should be compatible with that of ComplexTableField_Item::Link() in /users/tinchen1/www/dataobject_manager/code/DataObjectManager.php on line 644

Strict Standards: Declaration of DataObjectManager_Item::Fields() should be compatible with that of TableListField_Item::Fields() in /users/tinchen1/www/dataobject_manager/code/DataObjectManager.php on line 644

Strict Standards: Declaration of DataObjectManager_ItemRequest::Link() should be compatible with that of ComplexTableField_ItemRequest::Link() in /users/tinchen1/www/dataobject_manager/code/DataObjectManager.php on line 916

Strict Standards: Declaration of AssetManagerFolder::updateCMSFields() should be compatible with that of DataExtension::updateCMSFields() in /users/tinchen1/www/dataobject_manager/code/AssetManagerFolder.php on line 4

Strict Standards: Declaration of SortableDataObject::extraStatics() should be compatible with that of DataExtension::extraStatics() in /users/tinchen1/www/dataobject_manager/code/SortableDataObject.php on line 136

Strict Standards: Declaration of SimpleWysiwygField::Field() should be compatible with that of FormField::Field() in /users/tinchen1/www/dataobject_manager/code/simple_wysiwyg_field/SimpleWysiwygField.php on line 4

Fatal error: CalendarSiteTree cannot be applied to SiteTree without being a DataExtension in /users/tinchen1/www/framework/core/Object.php on line 484

What do I have to do now? Can someone help me out, please? Thanks so much!

The DataObjectManager (and related) modules don't work in SS3. Have a look at grid field instead.

Ok, thanks...but how does the grid field work? Do I have to install it like the DataObjectmanager?
I couldn't really find that out from the documentation.

GridField, much like the (Complex)TableField that DataObjectManager was built on, is included with SilverStripe core.