Everyone builds shieldbow on samira and it makes sense, it has crit and lifesteal which sam LOVES but i just wasn't feelin it so i fiddled with other mythics for WAY too long and eventually settled on this build. If you're thinking "but you need crit on your mythic so you can build IE 3rd" and you wouldnt be wrong but think about lethality Caitlyn, that doesnt have crit on its mythic and still builds IE and that build slaps. So now that we arent freaking out over lack of crit, lets talk about the build itself. Think about ezreal and how much he loves sheen, sam is very similar, her q is just slightly shorter range and you find yourself Q AA ing people A LOT so if that AA is just WAY stronger your quick trade damage is gonna be way better. and once you really finish trinity is gonna be stacking ad just like conqueror and just with the way samira works shes weaving attacks and stacking both all the time. and after trinity is bloodthirster or seesence reaver, essence is fantastic because of mana regen which becomes a lot more important with how much more you're using q, but if mana isnt much of a problem bloodthirster offers massive lifesteal and overheal sheild wich helps you SO MUCH (not to mention a ton of ad). and after those 2 you get IE and now you do nothing but slaughter, you chunk people from range or up close with trinity and its sheen ability, then you ult with trinity and conqueror stacked everything criting and lifestealing and being better than if you had sheildbow because everyone is half dead form sheen autos alredy. Now with your base understanding of this build lest move into more depth

https://media.discordapp.net/attachments/837814663021592641/878014845818126336/unknown.png

Conqueror is so perfect on Samira with the way shes half melee making it stack faster and how you will naturally stack it anyway with the way you stack your passive. triumph heals saves your *** all the time on samira like, ALL THE TIME. bloodline for more lifesteal of course. and last stand to let you slide into a triple kill from 20% health.

secondary runes are inspiration with boots and biscuts so you get a lil extra speed and your lane sustain just goes through the roof.

in the early game you before 6 you should be playing very passive, just stand behind minions and cs for the most part until 6, no need to get crazy yet. For the first few ways you shouldnt try to pull or push just try to keep it in the middle for the first few waves until you have almost enough for sheen, then slow push into their tower, recall and come back with sheen. But thats an ideal scenario, if things arent going according to plan just be as safe as you possibly can DO NOT DIE DURING LANE AT ALL COSTS WITHOUT TAKING AT LEAST 2 ENEMYS WITH YOU. This build is expensive and you really need to be getting max cs possible for everything to go right. Anyways lest say lane is going poorly and you're under tower stayin alive and getting cs, ping your jngl whenever you're under tower. If jngl comes fantastic just poke whil everyone fights tell enemy bot lane gets low then dive in and snatch the kills, you cant be getting crazy until level 6. Once you reach lvl 6 you can be more aggressive when fights look favorable, but DO NOT START FIGHTS IN LANE thats your support/jungle's job. You're an opportunist, poking, waiting, lurking, waiting for your moment to fly in and ult. In terms of when to back only do it when absolutely necessary or during your early game ideal scenario, or if you can push in a PHAT wave. And lastly in terms of items to buy when backing in lane is sheen first 99% of the time and then either boots(merc treads/plated steel caps) or straight into trinity, but that decision usually comes down to preference and situation.

P.S. remember to help with dragon when you can!

Mid is gonna super standard adc stuff, catch waves, steal jungle when you can, help take herald and drag. When it comes to fights braking out be very very cautious just poke if it is safe to do so and dive in only when you KNOW that you can pop ult and get that sweet sweet multikill(or any kill at all) but if you feel that that fight might not work out say **** it warning ping everyone and walk away, if you think that that fight will go poorly, it will, SO DONT ENGAGE IN IT(same thing goes for late game in that sense). Late game is gonna be the same thing again, cs, get objectives, and push with your team.

Also I HIGHLY recommend XSFN Saber's cs guide and all of his other adc guides, he's an incredible player and an incredible teacher when It comes to anything adc related. His videos helped me SO MUCH at improving on adc. BTW he's challenger so yk he knows what he's talking about

his adc cs guide(it teaches great habits too)https://www.youtube.com/watch?v=7rndmoPjnTU

Last few things to keep in mind:

this build inst as safe as the standard samira build, and if the enemy team is just one shout city this build probably wont work anywhere near as well as the standard build will, but you should still buy sheen first and just keep it in your back pocket until you can buy essence reaver 4th item if you end up having to run standard build.