To share a worksheet (or any other file) then create a new assessment as normal.
Underneath the assessment's Summary and Description there is an Add File button, click this to upload a worksheet, or notes, or some other file to accompoany the assignment.
When you've clicked the Add File button you will see a pop-up that will allow you to attach a resource from your computer. You can attach any numnber of files to an assignment but you can only upload them one at a time - so once you have selected a resource, click Attach and repeat the process.
Click Done when you are finished
Students will now see the assessment in TYP and will be able to download the worksheet that you have attached.