Let's break down the modes real quick.
ACT - Actively searches for a target type that you've designated in an area you've designated. Most specific and picky mode, great for preplanned attacks. The jamming pod is not strictly necessary for this mode, as you already give the system ranges via the PPs.
PAS - Searches for a transmitting radar that you designate via the HSD. Easy to switch between targets ad-hoc but doesn't know anything about target ranges, so won't loft the missile. That is, unless you use the jamming pod to provide ranges on the fly, in which case it will loft the missile.
RAND - Finds the highest threat radar signature ahead of you and targets that. Not sure about whether the jamming pod helps provide range in this mode.
SP - Self protect mode hasn't changed really, still throws a missile at the thing that's targeting/locking/shooting at you.
And some workflows. This is my personal process mixed with the patch notes, so I'm adding things, and is inspired by how I tested this on an MP server over the past couple of brief flights. I also haven't used RAND or SP yet, but I assume they work kinda like they say on the tin (see patch notes and previous documentation). ACT and PAS are the more involved ones, so that's what I'm going to go through here.
ACT -
Use the F10 menu to locate some targets, e.g. SAMs protecting a few airfields. Place PP1-4 points on each target (assuming you want four targets, do less if you want). Remember what each radar was on each point.
Use the ground crew radio to enter the aircraft config page. Select the four different radars you found in the previous step and enter them into each box, 1-4.
Update DTC, load it, and make sure you have WP36-39 present. You can also enter the SMS page for the LD-10, make sure it's in ACT mode, and cycle through the different target programs, 1-4, to ensure they don't turn red. If they turn red it got fucked up somehow. Redo the first two steps.
Take off, turn on the LD-10s, and warm them up the usual amount of time.
Select the PP point you want to shoot at as your WP.
When in range, make sure you're on the target program you want. Click softkey R4 in the SMS to command the LD-10 seeker to start searching for the desired signal. If the signal is captured, HUD/SMS will show RDY, otherwise it shows T/O (timeout).
Use the launch symbology on the HUD to get in the envelope and fire the missile. It will loft automatically.
PAS -
Get in the air and warm up your LD-10s the usual amount of time. Turn on your SPJ if you have one. Set LD-10 mode to PAS via the SMS.
If there are transmitting SAM/radar targets in the area, find them on the HSD and start flying towards them.
Take control of the HSD and center the bug/crosshair over the transmitting radar target on the HSD. Note HSD refresh time is pretty slow, take your time with the bug.
Press lock. This may be optional, but I do it anyways just in case. Nothing will visually change or show lock messages/symbology, but I'm superstitious until I test this thoroughly.
On the SMS, press softkey R4 to attempt to capture the desired radar signal that you put under the bug.
If the signal is captured, HUD/SMS will show RDY and a line to the transmitting signal will appear on the HSD (this line may be a SPJ-only feature, untested as of now), otherwise it shows T/O (timeout) in the SMS.
Use the launch symbology on the HUD to get in the envelope and fire the missile. It will loft automatically if you have the jammer installed and turned on.
There are numerous bugs affecting this system presently, but this more or less worked flawlessly for me. Check the bugs section for some issues with all this new fancy stuff and adjust your procedures accordingly.
