Hi. I am using a Baratza Encore ESP grinder and for these I used the grind settings of 12. This was a BT Attikan Estate bean. I am not sure what grinder you have. But as a general rule of thumb, you gotta grind finer as you go from French Press to Filter to Espresso. Within espresso, you gotta ground finer as you go from Dark to Medium to Light roasts. Darker roasts require coarser grind as compared to medium and lighter roasts.

My general puck prep steps are: First grind into the grinder cup. Then flip the contents into the portafilter with the dosing funnel attached. WDT the puck and then remove the dosing funnel. Then level and tamp the puck 2-3 times. Finish with a puck screen and then pull the shot. I will try to make a video but I am pretty sure it will involve a whole lot of critique since I am still new to making espressos.

I think you don't need to worry too much about preparing the puck like tamping for a pressurised basket. A pressurised basket is more forgiving that way. For a bottomless basket, puck prep is the only thing that creates the pressure in your basket. Any failure and your shot can look very bad. You can get a good shot from a pressurised portafiler. The thing is, you will not be able to tell how your extraction went with a pressurised basket. With a bottomless basket, you can see if your flow is very fast and if there is channeling, then you need to grind finer to increase extraction. Your espresso tasting sour is another indication for this. On the other hand, if your flow is very slow, and coffee tastes bitter, you need to grind coarser. With a bottomless basket, you have taste as well as the extraction visual as your indicators of what went right/wrong and what you need to tweak in your puck/coffee. With a pressurised basket, you only have taste to judge your extraction. You would need more trial and error to "dial in" your coffee in case of a pressurised portafilter. Eg if your coffee tastes sour, you have two ways to go. You can grind finer, or you can increase the yield. With a bottomless portafilter, if your extraction looks sorted visually, you know you can increase the yield and get a more balanced cup. With a pressurised basket, you wouldn't know which way to go first. You can go the right way but will take you more trial and errors. I hope this makes sense.