Mike -
Based on your last CE comment, I infer that you have access to the Harvard edition of EPM with an intro by Rorty and a study guide by Brandom. I found the study guide helpful at times, so I suggest that you keep referring to it even if it doesn't always turn out to be so.
Although your question was about section 10, just to make sure we're on the same page I'll set out where I understand Sellars to be headed. As always, the following is caveated by the observation that I speak with no authority whatsoever, so "IMO" should be understood to accompany every statement.
There are several things that make reading EPM difficult. One is that Sellars apparently was notorious for generally being hard to follow, a reputation that seems validated by EPM. Also, he throws in occasional seemingly extraneous material, eg, sections 8, 9, and 9 bis (there are two section 9's in the original!) which are possibly better skipped on the first reading. And his terminology - at least in the early sections - is often problematic since it relates to "sense data", which apparently is a somewhat nebulous concept that has changed between its inception early in the 20th C and the present and appears not to be currently popular in any event. Fortunately, as the essay evolves, references to sense data decrease and I believe they are mostly - if not totally - gone in the later sections.
In reading the essay the first time, I tried - and I suspect you are now trying - to translate the language into concepts that are more familiar today, eg, those from neurophysiology. However, Sellars explicitly avoids using neurological vocabulary, presumably for reasons that emerge only toward the end of the essay. So, such translations may or may not help.
As is usual in philosophy of mind discussions, the emphasis is often on the visual rather than sensations in general. This could actually make it more difficult for someone like you who is very familiar with visual processing. Even with my superficial knowledge of that processing I occasionally thought a statement seemed incorrect. Fortunately, little if any of the essay addresses that level of detail, so knowing "too much" about visual processing may not pose any real problem.
Now, on to section 10. Even before I started reading EPM I had encountered mention of those two distinguishable types of "inner episodes" several times, but out of context I couldn't quite see the point. I think part of the problem was that examples tend to be based on visual sensations, in particular those caused by "seeing red"; and the fact that colors - especially red - are so familiar makes it hard to accept that we have to learn about them (eg, the "Mary's Room" thought experiment). We are inclined to think that we "just know red when we see it". But if one focuses instead on sounds, eg, C#, it becomes easier (at least for those of us who aren't musicians with perfect pitch) to understand the difference between these two inner episodes:
(1) experiencing the sensation caused by hearing a musical note that within certain linguistic communities is called "C#"
(2) noninferentially knowing (ie, based on no additional information) that the musical note that corresponds to that sensation is called "C#" within those linguistic communities
Not distinguishing these two types of episodes is one example of the "myth of the given" - that one just "knows" about sights that are before one's eyes, sounds that are in one's ears, etc. (In trying to break entirely free from such misunderstandings, I have found it useful to try to imagine myself in the position of a baby who "knows" almost nothing about anything and has to learn even things that only a few years later will have become so familiar as to seem to have been known all along, ie, to have been "given" just by virtue of being alive and having an intact sensory system.)
The importance of all this is that the essence of the myth is that there is a body of knowledge that can be known noninferentially (the "given"), from which other knowledge can be inferred, and which is therefore foundational. The first part of the essay has the goal of refuting the existence of any such foundational knowledge.
I don't fully understand the significance of the references to "verificationism" and "operationalism" in this section, but it doesn't seem to matter - they never appear again, as best I recall. In the study guide, Brandom relates them to attacks on the myth by logical positivists (AKA, "verificationists", IIRC), who apparently denied the existence of inner episodes. Sellars argues against this denial of the myth later in the essay.
Another attack on the myth is by Wittgenstein, et al, who denied that inner - and therefore private - episodes could be premises (ie, foundational) for inferential knowledge since they are not amenable to public discourse and justification. Sellars notes that this opens the door for a version of the myth based on so-called "looks talk" - how something looks (ie, appears to be) from a person's 1-POV. While private, such reports are generally accepted as incorrigible since although people can be wrong about how a visual scene "is", they can't be wrong about how it "looks" to them. Sellars argues against this denial of the myth in the following sections.
On a first reading, it is easy to find this confusing since in the course of refuting the myth of the given, Sellars is also refuting attacks on it by others. Only after completing the essay does it become (relatively) clear why he does this.
I hope this helps, or at least doesn't just add to the confusion.