@mary1 in addition to what @mzimmerman provided, I will tell you what I do for situations like what you are describing. This procedure may apply to you and it may not. If your colleague has the exact same students as you do(or even if yours are a subset of those students), then your colleague exports the gradebook as described. You can then take that csv file and perform a slight tweak to the grade column headings and directly import the csv file and the grades into your course.
Procedure for the import
1) in you colleagues class lets say the assignment is Project10. In the csv it will have Project10(#######) where #### is the database number associated with that assignment.
2) in your class you create an assignment to hold the grade that you are going to import. give it the same name as your colleagues - that is Project10.
3) in your course the data base number in parentheses will be different than your colleagues. So all you do is take the csv file and change your colleagues data base number to yours and then import the file.
4) if there are more students in your colleagues course than yours (in other words you only want a subset of the students), Canvas will come up stating as such on the import and all those students can be ignored.
Hopefully that makes sense and may be something you want to consider
Ron