BC Framer® includes a library of details that may be placed using Manually Place from the Drawing and Markup ribbon.
You may add additional details via Libraries. File > Setup > Libraries: Construction Details > US > English > US - Floor Joist (English)
(Or another folder like US - Beam, if appropriate.)
Right-click on the folder name and choose Insert Construction Detail.
This will allow you to add a name, and then browse to the detail on your PC. (Detail Drawing)
You can edit properties as needed. Click OK to save Libraries and return to your drawing.
When you click Manually Place, you will need to edit the detail properties to choose the US\English\US - Floor Joist (English) list. Or wherever you saved the detail.
By default it always goes to the "Automatic" list which has a short list.
Select a detail in the list, and you will see a preview. Click OK.
Move your mouse into the drawing to place the detail.