1. How to change the size of chart nodes?

Chart size is determined by the chart layout applied to the chart. Select LargeOrganization layout and ByNodeSize chart sizing option to set custom size for nodes. All nodes will have the same size and the content will be resized within the node space available. See here.

2. How can I change the node shape?

See Node Border Shapes.

3. How to fill the chart in the available space with zoom facility?

Either select LargeOrganization layout and ZoomToScreen chart sizing option. Or select FlexiExtended layout. See here.

4. Where is chart orientations?

See here.

5. How can I give different settings for different levels of nodes?

It is in Level and Advanced tabs within Chart tab.

6. Where to change a node's content, photo and background?

It is in Basic tab within Node tab.

7. Where to change the alignments and margins of node's content/photo?

It is in Advanced tab within Node tab.

8. How to add new nodes and child nodes?

Right-click on the chart area and select Add root item(s) to add one or more nodes at the root level. Right-click on a node and select Add Children to add children (one or  ore nodes) to that node.