You may have already bookmarked the URL, which should be something like https://practicename.portal.accountants/ where 'practicename' is your advisor's business name.
Click (in the top right-hand corner) to find and select a file from your desktop or mobile device.
At the File to upload dialog, enter a description for your selected file. This will be the body of the email that's sent to your advisor. Be informative here, so they know exactly what they need to do with it.
Click Share. An email will be sent to your advisor and the document will be displayed in your Documents tab with an Upload tag.
If you need to upload another file, repeat from step 2 above.