I suggest you get a piece of paper and practice doing your beads making 3 sizes , S M L. Then do about 15 rows of them on paper. Once you able to pick up the correct bead size this save you later whe doing actual nails and having to file off in wanted product or perhaps having bead to runny so you have on the nail cuticles which flood.
If you dip your brush into liquid then wipe whole way pick up bead then if too liquid you can turn brush round and dap the back on your mani towel to take some excess liquid and this helps.
Google on utube there so many educational tutorials on bead application. By young nails or naio or nail educator.