I have copied a technical drawing from PDF in AI and i need to add more details. However there is a box around the whole drawing which does not let me reach the individual elements of the artwork. How do i get rid of the box and access the elements of the drawing?

I have copied a technical drawing from PDF in AI and I need to add more details. However there is a box around the whole drawing which does not let me reach the individual elements of the artwork. How do I get rid of the box and access the elements of the drawing?

I have copied a technical drawing from pdf into AI and i now need to edit this add more details. However there is a box around the whole drawing which does not let me reach the individual elements of the drawing to edit them. How do i get rid of the box and access the elements of the drawing?

I have copied a technical drawing from PDF in AI and i need to add more details. However there is a box around the whole drawing which does not let me reach the individual elements of the artwork. How do i get rid of the box and access the elements of the drawing?