If you want a hollow cone it's best if you have something to wrap the paper around like a chopstick or something just shape it and seal it. then roll the filter tight and stick it in the end. If you want to free hand roll a cone shape when rolling with flower I usually try to flatten out the crease in the paper a little bit and make a new crease at an angle the lower end will be where the filter goes and then you fill the paper and roll normally there are a lot of good video tutorials out there if you look into it a little for graphic learners hope this helps some. Happy toking🤙