I agree with @Johnnyq60… I think maybe that pistol is a bit small for appendix carry. But its going to depend on your build. Pocket carry may be the right ticket.
Having said that…
The very first thing you need to carry appendix is a dedicated appendix carry holster. I’m assuming you have the LightTuck? It is a very good holster and very versatile for a range of carry positions, but you are very likely going to struggle with comfort and concealment.I know, because I have one, it was the first holster I bought. You need a dedicated, appendix specific holster. It should have adjustable cant, ride height, a “claw” to tuck the grip towards your body, and optionally a foam wedge along the barrel. It is counter-intuitive, but a longer barrel is actually easier to conceal and helps with comfort. Many appendix holster makers will make slightly longer holsters for short barrel pistols (like G19 size for a G26 for example). I’ll put a list of some holster companies specializing in appendix at the bottom.
You will need a good belt if you don’t already have one. There are a couple other threads (use the search) that focus on belt selection. It must be sturdy and rigid to have success. The thing those other threads dont touch on much is the belt buckle. Depending on where your holster sits, and whether or not it has a sidecar, you will likely need to have your buckle off-center. Some buckles are very slimline, so this is less of a concern, but it is something to keep in mind.
Once you have a dedicated appendix holster, experiment with positioning from 2:30 to 12 o’clock. Most appendix carriers (if you aren’t using a sidecar) end up around 1 or 2 o’clock. You are looking for a spot where the barrel isn’t poking you on pelvic bone, and not jabbing you in your thigh/femoral artery area.
You then experiment with belt height on your waist. Sometimes keeping your belt higher or lower than your waistline can help with comfort or concealment.
Then you experiment with ride height. How high does the pistol sit in the holster. The deeper/lower it is, the more concealed it is. The higher it is, the easier it is to grab the grip. As a starting point, it should sit where you can just fit your fingers around the grip while its on your belt. Adjusting the cant (the angle off of vertical) can sometimes help sit the pistol a little lower or higher and still allow a good grip while maintaining concealment.
A good appendix holster will have a “claw” or “wing” (or sometimes called a “wing-claw” ¯\_(ツ)_/¯ ) that levers against your belt to push the grip of the pistol back towards your body. These are a must have on any good appendix holster.
Many appendix holster makes will offer some sort of foam wedge attachment, or a small bump in the kydex, along the barrel of the pistol to push the bottom barrel end out from your body, which levers around the belt to push the top of the pistol in closer to your body. The foam wedges also help with comfort since it is foam against your body instead of hard kydex. Too small of a wedge, and there is little to no benefit (other than comfort). Too big of a wedge and you have a very odd bulge in the front of your pants. If you search around on Youtube you can find DIY solutions like taking the heel of a shoe insert (the gel kind) and using that as the wedge.
A very common issue on appendix carry is called the “tip out”. That is where the top of the pistol tips out and away from the body reducing concealment and very probably increasing discomfort as the barrel is then likely poking you in the pelvic area. The pistol, holster, belt, body combination has the pistol “tipping” around the fulcrum of the belt. If too much pistol is above the beltline, it will tend to tip out. This can be mitigated by longer holster barrel length, foam wedges, reduced ride height, less belly flub 
Here is a list of some appendix makers I either have used myself or know someone who has. This is far from exhaustive there are many really good appendix carry holster makers. Hopefully this gives you an idea of what to look for. Look out for IWB (Inside the Waist Band) because what you want is AIWB (Appendix Inside the Waist Band).
- JM Custom Kydex - great appendix carry holsters. The Wing Claw 2.0 is my nearly daily carry.
- Tier 1 Concealed - They make some fantastic sidecar holsters, they are one of the few that makes holsters around the Streamlight TLR-7 and TLR-8 series weapon lights. I have an Axis Elite I’ve been very happy with.
- Keepers Concealment - One of the OG appendix makers, he specializes in carry for “large fellows” and if you search around on Youtube you can find him on various other people’s channels giving tips on how to conceal appendix with a belly (and even if you don’t)
- T.Rex Arms - Another one of my first holsters. These tend to sit very high, so for me was harder to conceal, but the draw time is much faster. Most of the T.Rex products are geared towards “going faster”. Available with and without sidecar.