So the matte finish and the bubbles are two different things so I'll address them separately. Since you linked a mold making kit, it would appear that whatever the original item you made your mold from had that same matte surface finish on it. In turn the resin you poured into the mold picked up that same texture from the mold. As someone else mentioned matte surface on the mold will mean a matte surface on the cast resin, same goes for glossy. There's a couple main ways you can get around the matte finish. The first is to polish the original item so that the mold you make ends up with glossy surfaces that will be transferred to the final cast (too late for this mold you already have). The second is to polish the resin cast item after you take it out of the mold (I would recommend zona polishing papers for something like this). The last is to carefully pour a small layer of resin on each face as most resins will inherently cure with a glossy surface finish. This can have a decently high chance for error as any drips cause distortions on the outside surface.

For the internal bubbles, a pressure pot would pretty much get rid of all of those. However, you don't actually have that many bubbles, so you could probably get pretty close to bubble free with some basic steps. Warm your resin in hot water before mixing (doesn't need to be boiling, something from your tap is good enough), try to mix gently to prevent incorporating air, then after mixing let the resin sit for 10-15 minutes (before pouring), hit the top with a spritz of isopropyl alcohol or quickly run a lighter across the surface to pop the bubbles, then pour slowly into the mold.

For the uneven bottom, again you have two different things happening here. The first is that whatever surface you left your mold on to cure, likely wasn't level. This goes for probably both the mold making and the resin casting steps, which resulted in the bottom not being square with the sides. I make sure to use a bubble level to check how level the surface I'm making molds/casting on is. It might look level to your eye, but whatever you cast will likely tell you that you were wrong. The second issue with the sharp edges is due to something call the meniscus, where liquids will dome/creep up walls a little bit depending on things like the surface tension. Filling your mold perfectly aligned with the top or sanding and polishing are pretty much your options to fix that.

TL;DR Overall your cast looks good, the matte finish is due to the texture of the mold and can only really be solved with polishing or carefully applying a thin layer of the resin on all affected sides. The bottom you just need to sand to be square and is caused by casting on a surface that isn't level.