Workspace

I am new to Smartsheet. I am looking to create a workspace for every project that we have going on. Question is - we currently keep all pertinent documents in dropbox and I would like to move these to Smartsheet so all project documentation is contained in one place. I have not found a way to save pdf files, word docs, excel spreadsheets in the workplace other than saving them as attachments. Is there a way to save these documents in specific folders on/in the workspace and not just as attachments?