https://dna-explained.com/.../concepts-centimorgans-snps.../
I asked on another site how cms were counted and the relationship to SNP's and someone kindly gave me the above link which explains it clearly and also discusses small matches. Worth a read if you are interested.
Sherry, in addition to Roberta Estes (whose blog you linked to), ISOGG--the International Society of Genetic Genealogy--also provides very good information.
You're welcome. The ISOGG website has a lot of information, and I don't pretend to understand it all. One thing I used now and then is their Genetics Glossary.
I've got some other resources listed here.