From my previous life, I looked at loads on flights all the time and this is how it was done with us:

Consider this a 737 with 12F and 116Y seats

CLASS SEATS AUTH BKED AVAIL
F 12 12 4 8
Y0 116 126 118 8
Y1 119 118 1
Y2 100 118 -18
Y3 85 118 -33
Y4 65 118 -53
Y5 65 118 -53
Y6 20 118 -98

For F, it is easy. It would read that there are 12 seats on the plane, yield managment will sell 12 seats in F (meaning they will not oversell), 4 seats are booked in F, and 8 are left.

For coach it was a little more difficuly. As you see there is a Y0-Y6. I don't recall exactly, but it was similar to this. Let's take DL's typical coach fares - Y,B,M,H,Q,K,L,U. Those are eight fares clases. Y0 would be Y, Y1 would be B, Y2 might be M and H, etc.... It means that different fares codes might pull out of the same bucket.

For the listing of Y0 (a typical Y fare), it is similar to F. You see there are 116 seats in Y, there are 126 Y0 seats authorized (the flight could eventually be oversold by 10), there are 118 total Y seats booked (flight already oversold by 2), and there are 8 more Y0 seats available for sale. For the listing of Y1 (a typical B fare), there are 119 seats authorized. This means of the total 126 authorized to be sold on the flight, no more than 119 can be booked in Y1 and lower. The last 7 (126-119) must be sold in Y0 inventory (typically Y fares). Wih the availability as shown, since 119 seats are authorized in Y1 and 118 are booked, there is 1 seat left to be sold in Y1 class.

For Y2, 100 seats are authorized at this fare or lower, 118 are already book, leaving the availability in Y2 and lower at -18, meaning these can't be sold anymore. This goes on and on down to Y6 which are the sale fares typically.

So in ITN expert mode, on UA.com, and on a TA screen for availability, you will see:
Y8 B1 M0 H0 Q0 K0 L0 U0

Now the above numbers aren't typical, just an example. Routes like ATL-MCO with 200 seats in coach might be authorized (from Y0 to Y6) 215, 210, 205, 200, 180, 150 - meaning they would sell 150 seats at the lowest fares - and oversell the plane by 15 - not many for a 200 seat coach section since families going to Florida will typically show up.

A "business" ORD-DCA flight with 150 seats in coach might be 190, 130, 100, 50, 20, 10. They are driving the yields up on this flight becasue they know the businessman will pay it. Also, they will oversell by 40 since many times business guys might be a no show.

Hope this helps.