Sorry I realize this might be a very basic question but how can I select which photos I want to work with once I have imported them.

Do I need to import into LightRoom first then trim unwanted photos or can I deselect and delete photos from my LRTimelapse Basic Workflow

Thanks

You can delete Photos from within LRTimelapse - but they will then be deleted from the harddrive.
Another way would be to split sequences, by selecting the unwanted photos and clicking with the right mouse, then "new folder from selection".

There is no way to just render a subsequence of one folder. This might only be accomplished by removing the unwanted photos from the LR-Catalog before rendering, but I would not recommend this.