Whether used for data or layout, tables need a simple cell format and appropriate markup.
Using the Tables menu in the Rich Content Editor will allow you to set up the various properties needed, as mentioned above.
See Insert a table using the Rich Content Editor (Canvas) for an illustrated guide and/or the following:
Create Accessible Tables - A webpage of Canvas tips from Penn State University
With the entire table selected, using the Design tab of the Table Tools will allow you to set a Header Row and Header Column.
With the entire table selected, right-clicking will bring up a menu that allows you to Insert a Caption.
See Create Accessible Tables in Word for a tutorial and/or the following resource:
Creating Accessible Tables - A video (3:21 minutes) by NC State IT Accessibility