@Bjodonnell123, you will want a spout for your can of powder to dispense the powder into the measure. I'll say it again, " When shooting a flint lock, only use real black powder. The substitute powders do not work well enough to even consider." At this stage in your learning of the finer points of shooting a flint lock rifle, you can use 3Fg powder. Use 10% less than the suggested 2Fg loads. The 3Fg will also work in the pan as 4F powder or Swiss Null B can be harder to find than real black powder.
Locate a traditional muzzleloading gun club. The members will help you learn about and care for your rifle.
Search on the Forum for more information on starting out.
Don't be afraid to ask questions here on the Forum. You will get answers.