Hot-bar/Action-bar are the same thing technically. I will try to explain. I am using bartender 4 and has different command to switch action bars(/changeactionbar). Take following 3 macros.
Macro 1 goes on bar 1 button 1
/castsequence reset=target Howling Blast, Plague Strike, null
/castsequence reset=0.5 0,0, Howling Blast
/castsequence reset=0.5 0,Frost Strike
/castsequence reset=0.5 Obliterate
Macro 2 goes on bar 2 button 1 & 2 (same button as bar 1)
#showtooltip Plague Leech
/castsequence reset=0.5 0,Horn of Winter
/castsequence reset=20 Plague Leech,Plague Strike,Howling Blast
/cast [combat] Pillar of frost
/use [combat] 13
/use [combat] 14
Macro 3 goes on bar 1 button 2 (should be used when the target is below 35%)
#showtooltips Soul Reaper
/castsequence reset=0.5 0,0, 0,Howling Blast
/castsequence reset=0.5 0,0,Frost Strike
/castsequence reset=0.5 0,Obliterate
/castsequence reset=0.5 Soul Reaper
/swapactionbar 1 2 (If you use Bartender 4 use /changeactionbar 2)
Setting up Bartender 4:
Step 1 In configuration select Bar 1, enable it. Select State configuration
Step 2 In state configuration tan check Enabled and then check Action-Bar Paging.
Repeat step 1 & 2 for Bar 2 as well. and further more to bar 3, 4, 5 or 6 if you need to swap all those bars. Note: bar paging/swapping only works for bars 1-6.
Once you have done this, go back to General Setting tab for the bars and uncheck enabled for bar 2-6 so that they are hidden. Note don’t uncheck “enabled” on Bar 1 as we will be using that bar.
At this point Bartender 4 is all setup so close the configuration.
Creating Macros: Note: you will need an ad-don called SuperDuperMacro for most of these priority style macros as it allows longer than 255 character macros.
Now open macro windows by entering /m or /macro in the chat window and create a new macro global or character specific. Create the above 2 macros provided by Captivation_Li
Put macro 1 in bar 1 button 1. Click it once and it will disappear. This is because the line /changeactionbar 2. Now the action-bar 1 has changed to action-bar 2. Now put macro 2 in bar 2 and same button as bar 1 which is button 1.
Now when you click macro 2 it will change to action-bar 1 and you will see macro 1 in the same place. As you click button 1 over and over you will see that button 1 will keep switching between macro 1 & 2.
When you select a target, while you are in combat or out of combat, first click will trigger Macro 1. Macro 1 will start of by applying Frost Fever (Howling Blast) and switch and try to Plague Leech and fail & switch bar and apply Blood Plague (Plague Strike). At this point, Macro 1 will always keep Frost Fever up and every time the bar switches, and you hit macro 2, it will go through a cast sequence of Plague Leech, Plague Strike, Howling Blast.
Frost Fever and Blood Plague are always up and Plague Leech gets used on every cool-down. there might me some delays on the Plague Leech but that’s due to GCD and Macro 1 trying to cast higher priority spells.
Now if I want to use the Soul Reaper Macro (Macro 3) it will go in action-bar 1 button 2 and on action-bar 2 I would also put Macro 2 on button 2. This way when ever I hit Soul Reaper Macro and the action-bars are switched, I will get the Macro 2 on the same button as well and the rotation goes on smoothly.
I hope you understood the concept.