Thank you for your post.
To add components to your component library follow the steps below.
1) Download the components into a blank, new SketchUp model.
2) Use the PlusSpec BIM Tool to add additional info to each component, which will be what appears in the takeoff.
3) Right-click on a BIMed component and select 'Save As..' and then save them on your computer (e.g. My Documents or shared drive). Note: I would recommend to set up a folder structure so that the components can easily be found after they are saved to their respective areas.
4) Repeats Step 3 for each component.
5) Drag and drop the component you need into your model. It should then import into the model with all the info entered into the BIM Tool. The info can be view and edited by selecting the component and then selecting the BIM Tool.
Note: If you need to update the info for a component for next time, edit the component using the BIM Tool then repeat Step 3 to save the updated component.
Would you be able to please let me know if this works for you?