CRA (Canada Revenue Agency) has a number of online products that may be useful and relevant to members of CARP. They are intended to assist people with their tax obligations and help answer the questions they may have.
On the CRA website there is a section dealing specifically with the needs of seniors, which can be found at www.cra.gc.ca/seniors. Lots of answers to commonly-asked questions can be found at the links compiled at that site.
CRA also has videos which deliver much of this information in a format that may be more engaging. A couple of popular ones that are relevant would be: Preparing your Income Tax and Benefit Return: http://www.cra-arc.gc.ca/vdgllry/ndvdls/srs-prprngrtrn-eng.html. Tax Measures for Persons with Disabilities: http://www.cra-arc.gc.ca/vdgllry/ndvdls/srs-txmsrs-pwd-eng.html. CRA also has DVD copies of these videos in the CRA office, available on loan.