It sounds like you're new to iLogic and the Inventor API but not VBA. For starters, in the top right of the Inventor window is a drop down menu where you can access the API Help file:

Keep in mind that iLogic is a custom plug-in for Inventor that can't do everything the full VBA editor can do, i.e. iLogic can't perform With Events and the routines with Classes and Subs are also limited, the pros with iLogic is the ease of building code quickly by directly referencing document parameters, iProperties, etc., with the use of iLogic snippets found to the left of the iLogic window. You'll also find that VB statements like let and set can't be used among other things.
For your particular project, I'd recommend looking through the BrowserNodes Collection for a selected node and then get the native object from that:
ThisDoc.Document.BrowserPanes.ActivePane.TopNode.BrowserNodes.Item( Long Value As Index Number or String As Label ).Selected = Boolean