This will be my first tutorial, and on how I magnetized my Hive Tyrant to accommodate the standing pose AND the tail-elevated flying pose. I've seen a few other tutorials, but they only magnetize the standing pose and neglect the 'tail-elevated' flying pose (which I think just looks way too badass to leave out)
As a side note, I JUST got into Warhammer 40k a few weeks ago and haven't had much experience with conversions and such, especially for GW miniatures. So if I do anything that looks noob, please tell me; I want to learn as much as I can
Step 1
I started out simple and magnetized all the joints that we will need for the weapons, shoulders, torso, and abdomen attachments.

shoulder sockets
(I'll explain why there's a small hole there a little later)

neck joint

bottom of torso
(dont mind the blue tac; that was for a mistake I made earlier)

this is the ball-abdomen joint; i magnetizing the top and the bottom of the piece

bottom of the abdomen

head

the various weapons
Step 2
I then corked the base and added brass rods to pin the model's feet. I drilled the holes into the cork/base with a pin vise.
This is the finished standing pose
Now onto the flying pose - this part gets a bit tricky
[The main difficulty of the getting the flying pose right was trying to balance the wings. With the 'forward leaning' pose of the flyrant, the wings would droop or just fall off if you moved the model in an actual game. To fix this, I had to magnetize the wings AND add brass pins to the wings as well to anchor them onto the carapace. Pictures of this will be shown further down.]
Step 1
Place another magnet on the bottom of the flying-pose abdomen, the same was as the original abdomen. But also, glue a brass pin into the abdomen as well, leaving it stick out and bend it accordingly(more detail in next step)
Step 2
Drill a small hole into the bottom of the V-shape of the ball-joint piece. MAKE SURE IT ALIGNS WITH THE BRASS ROD STICKING OUT OF THE ABDOMEN PIECE IN THE PREVIOUS PICTURE! The bent pin should slide snugly into the hole you just drilled (DO NOT glue the pin into the ball-joint piece; it is supposed to be removable)
Step 3
Magnetize the wing joints so they line up accordingly with the shoulder socket. But also, remember that small hole I in the carapace in the first picture? THIS is why it's there; I glued a brass pin into the wing and bent it which will serve as an anchor so the wing will stay on the body.
Do this for both wings.
DO NOT GLUE THE WING-PINS INTO THE CARAPACE. ONLY GLUE THE PINS INTO THE WINGS. THEY'RE SUPPOSED TO BE REMOVABLE.
This will take some time and patience on your part; you have to bend the pin at such an angle so that the wings stay put, especially because the 'leaning forward' flying pose really disrupts the balance of the wings.
Step 4
Pin the flat part of the tail with 2 brass rods. This will anchor the flying pose to the base, exactly like the standing pose seen earlier.
With the cork base, there is enough friction so that you wont have to glue the pins into the base for it to stay. This will allow you to change between both poses on the fly!
More pictures/notes
You can see that the pins are practically invisible in the wings when you put them on correctly. Pretty flush for the most part.
Here's the Flyrant in his pose with stable wings firmly attached!
And here are all the pieces we should have thus far!
I know this tutorial is a bit vague on the specifics, so if you have any questions or problems, I'll try my best to answer them. I'm still very new to the miniature hobby so for me, this project was definitely a whole-day affair and fairly frustrating.