zivale:
Yes, placing the object(s) in a folder, then adding this folder to the project's libraries via the
Library Manager is the way to handle this.
For the material, you should add this material to your template file so it is already present in the project, rather than using the Attribute Manager to add each time. Or you could resave the object using one of the default materials in your template. Materials are part of the project file, not the object. If you are interested in learning some GDL, you can alter the script of the object so the material choice is parametric rather rather than hard coded into the object.
You should add a Signature to your Profile (click the Profile button near the top of this page) with your ArchiCAD version and operating system (see mine for an example) for more accurate help in this forum.
David