Do you have any advice for a newbie
Yes, first of all understand the important distinction between a "Massage Parlour" and a "Massage Shop".
The terms are NOT interchangeable.
A "Massage Parlour" is a place where you are unlikely to get any massage but will be offered FS. In the old days probably staffed by English ladies but then the EE ladies "invaded". Unlikely to see Chinese or Thai ladies there. You wouldn't take your mother or sister to such a place and they wouldn't venture in by themselves.
A " Massage Shop" is what, I believe, you are referring to and others have already given you advice about. Almost exclusively Chinese or Thai. Occasionally they may use the term "Parlour" but the older ones amongst us will understand the term to mean what I've described above.
You could take your mother or sister to a shop. Some are exclusively legit, i.e. they only provide massage and there are NO extras. Most though do offer a little "extra" but it is NOT guaranteed. One of the reasons could be because your, or someone else's mother, is being massaged in an adjoining room.