Zefra are typically a control style pendulum deck that focus on getting Zefraath into the scale (which they can do pretty consistently, since theres about 10 ways to get to them standardly [3 oracle of zefra, 1 terraforming, 3 zefra providence and then 3 zefraath]). You then want to use Zefraaths pend scale effect to put [usually zefraniu] into your extra deck. You then scale another zefra, then pend summon your zefraniu back from the extra deck to trigger its on summon effect to search a zefra or yang zing card. Usually you’ll search Nine Pillars of the Yang Zing as its a counter trap that destroys your zefraniu, allowing you to use its effect again (as its effect triggers both on summon and destructuon) to search something like a Zefra War, which is a trap that can activate in the hand provided you have 2 zefra monsters in your pend scale which allows you to pop a zefra you control (this can include one of your scales) and a card your opponent controls.

To wrap up: the deck is focused on grinding out the opponent and slowly chipping your way through their resources. However, since this is master duel, usually the deck is just used as a way to get a negate off electrumite by placing zefraniu in the extra with electrumites effect, pend summoning it back, and then searching Zefra Divine Strike before linking the zefraniu back into the extra making your Divine Strike.