Well call me biased, but....
The first 4 chapters of Carpenter's Complete Guide to the SAS Macro Language, 2nd Ed. were written with you in mind, and were designed to be read and studied linearly (not as a reference manual).
https://support.sas.com/pubscat/bookdetails.jsp?pc=59224
The other book that you want to look at is Michele Burlew's SAS Macro Programming Made Easy, Second Edition
https://support.sas.com/pubscat/bookdetails.jsp?pc=60560
She does a good job discussing the ins and outs of the macro language.